This web page documents the the GNU cssc package for working with
SCCS files.
Copyright (C) 1997,1998,1999,2000,2001,2002,2003,2004 Free Software Foundation, Inc.
Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies.
Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one.
Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that this permission notice may be stated in a translation approved by the Foundation.
The GNU CSSC program is designed to be a compatible replacement for the traditional Unix SCCS suite.
While it is strongly suggested that new projects not use this package, sometimes existing projects require the use of SCCS files. While conversion to other formats is possible, this is also sometimes impractical. See the documentation for CVS and RCS. See What is CVS?. See also the manual pages for RCS.
GNU CSSC is published under the GNU General Public License, which is designed to protect your rights, as the user of this program. You have the right to modify this program, and distribute it. You also have responsibilities to those to whom you distribute copies, as detailed in the license. See GNU General Public License.
GNU CSSC was originally based on the public-domain package MySC, which was written by Ross Ridge. The enhancement work was done by James Youngman.
The sccs program itself and its accompanying documentation
sccs.me and sccs.1 were written by Eric Allman, and are
covered by the BSD license (see BSD Code).
By far the easiest way to use CSSC (or indeed SCCS) is to use VC-mode in GNU Emacs. See Version Systems.
If you can't use VC-mode, the BSD command sccs is a good
interface to the SCCS suite (and hence CSSC).
Other than that, you will need to use each of the programs in the suite individually.
adminTo create an SCCS archive of a source file foo.c, do
admin -ifoo.c s.foo.c
This creates the archive file s.foo.c and initialises it
with the current contents of your source file, foo.c. If you use
Emacs as your editor, you can just use C-x v i instead.
Another frequently-used option is -b, which indicates that the
file is to be treated as a binary file rather than as text. You might
want to do this because the file actually contains binary data, or just
characters that have other meanings within an SCCS file, for
example ^A, the character whose code is 1.
-axxxget -e and delta). Users
must be specified by name and groups by numeric ID.
This feature is often used in conjunction with a setuid installation of
the sccs driver program (see sccs). This is not a good idea
because the CSSC suite is not secure (see Known Problems).
-b
-n or -i options.
This option is not available if binary file support is turned off
(see Interoperability) though this can be re-enabled if necessary
with an environment variable (see Environment).
-dF
-exxx-fF[xxx]
-fv/tmp/checkit sets the
MR-validation flag to /tmp/checkit.
-h
val. Some problems with the SCCS file may not be
diagnosed.
Warning messages may be emitted, indicating things that may or may not be wrong (e.g. time apparently going backwards), but if no actual errors are encountered, the exit value will still be zero.
This option is silently incompatible with all the other options; the
specified SCCS files will not be modified by admin if the
-h flag is used.
-ifoo-n option.
-mMR-list-m option causes delta to
fail.
-n
-i is also used, the new
file will contain control information but the body will be initially
empty. Some versions of SCCS require the -i option to
be specified if -n is used. Therefore for greatest
portability, specify -i/dev/null if you want an empty initial
body. Interoperability.
-rN1.2 or
1.8.2.1). CSSC also allows this, but emits a warning. If
you use the -r option, you must also use the -i
option (not just the -n option). If the initial SID you
specify is not on the trunk, some tools will fail to work with the
resulting file. See also See SCCS Version Differences.
-tdesc-i or -n is used).
-V
-yadayada-y, the
comment is recorded as empty. The following word in the argument list
is not used as the comment. Note that this behaviour is different
to most Unix programs, but is the same as the behaviour of traditional
SCCS.
-z
Flags are set and cleared with the admin program. See admin.
b
-b option of get
(see get).
e
-b option of admin at
the time the file is created (or if admin takes it upon itself to set
this flag automatically), and cannot be unset. The circumstances under
which this can happen are discussed in Interoperability.
f
i
get and delta exit unsuccessfully when the
Warning: No id keywords message is issued.
j
j flag overrides this.
n
-r option to get is used to
skip releases. These empty releases can later serve as branch
points.
x
admin -fx generates a warning to this
effect. If CSSC is simply processing a file which already has
this flag set, no message will be generated. See
Interoperability for more information on compatibility between
CSSC and other implementations of SCCS.
c
f
d
get command is given
without the -r option. The default behaviour for get is
defined in get.
l
get -e. The special value a denotes all releases.
q
%Q% keyword as described in
Keyword Substitution. This flag is referred to in the output of
SCCS as csect name, and is variously referred to here as
that, or the "user flag" or the "Q flag".
m
%M% keyword as described in
Keyword Substitution.
t
%Y% keyword as described in Keyword Substitution.
v
y
admin -fyQ,M,Y restricts keyword expansion so that
%Q%, %M% and %Y% are expanded, while other
keywords such as %Z% are not.
This flag is an extension introduced by Sun Solaris 8. See
Interoperability for a discussion of the interoperability of
CSSC with other SCCS implementations.
MRs are identifiers that can be specified when checking in a
revision using delta (or even using admin, when creating a
file).
If the v ("validate") flag is set, the user running
delta is prompted for MR numbers as well as revision
comments. If this flag is not set, no validation is performed and no
MR numbers are prompted for. If the -m option is given on
the command line for delta, the user is not prompted.
MR numbers are not required by CSSC to be actual numbers; they may contain any non-whitespace printable characters; other implementations may not be so flexible.
MR numbers are frequently used to tie code revisions to other things, for example engineering change management documents or bug-tracking databases. If your change management systems are computer-based, you can use the validation program to ensure that the offered MR number is valid and that the calling user is allowed to change the file.
The first argument passed to the validation program is the name of the g-file and the following arguments are the MR numbers offered. The validating program should return zero if all the MR numbers are acceptable.
One might think that it would be useful to associate the MR number
with the action of checking out for a modification (get -e), but
this is not possible with SCCS. If you want to do that kind of
thing, you must use a more advanced system, for example GNU CVS.
cdcThe cdc command allows you to add comments to the commentary for
a particular delta in an SCCS file. Any delta in the file (other
than ones removed with rmdel) can be modified.
If a comment is not specified on the command line, comments are accepted via standard input.
If the special argument name - is being used, this means that a
list of files to operate on is being read from standard input, and
therefore the -y option is mandatory in this case.
The new comments are prepended to the existing comment for that delta,
followed by a line of the form *** CHANGED *** yy/mm/dd hh:mm:ss
who. This is followed by the original comment. Comments cannot be
removed using cdc, but they can be added.
Only three options are supported:-
-mMR-list!), then the
indicated delta is removed from the existing list of MRs for the
delta. The file comment is modified to indicate what MRs have been
removed. If an MR to be removed is in fact not present in any
case, this is silently ignored. and the comment is not updated for that
MR. If you do not also want to add to the comment for the delta,
specify an empty comment option (that, is, a bare -y).
-rSIDrmdel.
-yCommentcdc. An empty -y
option can be used to indicate that the commentary for this delta is not
to be modified (this is only useful when the -m option is used).
If the -y option is not given, the user is prompted for comments.
combThis program is not yet implemented or documented in the manual, there are no tests for it in the test suite yet, but it is part of SCCS so it will eventually be implemented.
deltaThe delta command is used to add a new revision to the ones
already stored in an SCCS file. Before being able to do this you
need to run get -e to check the file out for editing.
A new revision is created by the delta program. These revisions
are each identified by a unique SID. A SID looks like
1.2.3.4, where the four numbers are the release,
level, branch and sequence numbers.
New revisions on the main sequence (the trunk) have no branch or
sequence numbers and so just have two number components (1.2, for
example).
When a new version is checked in, delta usually prompts for
comments describing the changes just made. At this point you can enter
any comments, separating lines with backslash-newline pairs. An
unescaped newline terminates the comment, allowing operation to
continue.
Sometimes, running delta results in the creation of a branch in
the SCCS file; this is controlled by the get command at the
time the file is checked out for editing (see branches).
The delta program checks to see if you are authorised to check
in a delta to this file. The list of authorised users can be
maintained with the admin program (see admin). If the
MR-validation flag (see Flags) is set, you must also supply a
valid MR-number in order to be able to check in your change.
deltaAlthough there are several valid command-line options for delta,
they are not frequently used; the most common usage of delta is
delta SCCS/s.umsp.c
and this command simply applies the changes to the file umsp.c to
the SCCS file which tracks it. Though it is possible to specify
the comment and MR-number for this change using command-line options,
it's more common to type them when prompted, unless delta is
being driven by another program; either way, it's unusual to specify
options for delta on the command line.
Note that the filename you specify on the command line is that of the
SCCS file, not the filename of the working file. The BSD wrapper
program, sccs(1), will guess the correct filename for you, but this
doesn't happen unless you do actually invoke it (sccs delta
umsp.c for example).
delta-gsid-Listget. The list is a list of
SIDs separated by commas, or can contain ranges of SIDs (these
are indicated by a dash). Untested.
-mmr-listdelta will prompt for MR numbers if none
are given on the command line. If the v flag has a non-empty
value, as opposed to just being set, then the supplied list of MR
numbers will be verified using that program. The requested delta will
not be made if this validation fails (the validation program returns a
nonzero exit status).
When the v flag is set, deltas must be checked in using
this flag. If you are using Emacs's vc-mode, you can do this by setting
the variable vc-checkin-flags to "-m2677" if the MR
with which you are working is numbered 2677, for example.
-n
get
command.
-p
diff is echoed on the standard
output.
-r
-r command-line option is
used to specify which checked-out version this change is in reference
to. When get is used to check out a version for editing, it
announces two SIDs:-
3.1
new delta 3.2
402 lines
One identifies the version forming the basis of the change, and the
other specifies the SID that the new version will be assigned once
it is checked in again. Either of these two SIDs (in this case,
3.1 or 3.2) can be used for the -r option of delta.
-s
-y
-y. If this option is not given
on the command line, delta will prompt the user for a comment.
getThe get command is to retrieve previous revisions from an
SCCS file. With the -e option, it also locks the gotten
revision so that a modified version can be checked in later using
delta.
getget. Below,
s.foo.c denotes the name of any existing SCCS file.
get s.foo.c
s.foo.c into the
file foo.c.
get -Gbar s.foo.c
s.foo.c, into bar rather than the
default foo.c. The file produced by get is often referred
to as the "g-file".
get -r1.3 s.foo.c
s.foo.c into foo.c. The -G
option can be used to set the name of the gotten file.
get -p s.foo.c
-r option could also be used to specify some other revision.
Unless you specify the -k or -e option, the retrieved file
will be created read-only.
get-aN-b
-e option. If the -e option is not given, or if
the b (branch) flag is not set in the SCCS file, this option
has no effect; a branch is not made. If the version to be checked out
for editing has a successor, a branch is created whether or not the
-b flag is present (see branches).
-cwhen-c92, you get the latest version which was available
in the year 1992. It is possible to give four digits for the year as a
CSSC-specific extension, but only if none of the other fields are
omitted. If only two digits are used and the resulting value is less
than 69, the year is assumed to be in the twenty-first century
(see prs options and Year 2000 Issues).
-D
-e
j flag is set (see Flags), get -e will
fail if someone else already has the file locked. If the list of
authorised users in the SCCS file is not empty, you must be in
that list in order to use this option.
-g
-Gfoo-ilist-x.
-k
-e is specified. The gotten file is writable.
-l
-lp
-m
delta which introduced this line to the file.
-n
-m option.
-p
-rX-s
-t
get is to get the highest revision on the trunk. The
-t option only modifies this behaviour in the situation where the
topmost trunk revision is a branch point. In this case, the -t
option causes the topmost revision on this branch to be retrieved. In
other words, the -t option removes the restriction that the
retrieved version should be on the trunk. This option is used by
comb (see comb) and by the driver program sccs from
BSD (see sccs).
-V
-wXXX%Z%%M% <TAB> %I% as the substitution
value for %W%.
-xlistNormally, editing revision 1.1 of a file produces revision 1.2. Editing that produces revision 1.3, and so on. Sometimes, however, we need to make a change to an earlier version which has already been superseded.
This might happen, for example, when a bug has been reported in a released version of a file; a rapid bug-fix is required, but you're in the middle of working towards a new release. A viable strategy is to make a branch at the previously-released version, modify that to fix the bug (and release this bug-fix). Meanwhile, development can be continued along the "main trunk", and the same bug-fix can be incorporated in this, ready for the next release later on.
When you check out a version of a file for editing, CSSC tells you
what the SID of the new version will be. For normal progress along
the trunk, the level number is incremented. This is the second
numeric element of the SID. In general, a SID is composed of
four numbers R.L.B.S, where "R" stands for "Release", "L"
stands for "Level", "B" stands for "Branch", and "S" stands for
"Sequence number" (not the same as the sequence numbers produced in
the output of prt).
Trunk revisions have only two components; you can think of the branch and sequence numbers as being zero. Non-trunk revisions have four components. When a branch is created from an existing SID, the release and level numbers are copied, the branch number is set to the lowest unused value for that release and level, and the sequence number is set to one. Hence the first branch from version 1.1 will be version 1.1.1.1, and if a branch is made from that, its SID will be 1.1.2.1.
Branches are made from any given version when that version already has a
successor. For example, a get -e on version 1.1 will result in a
branch (1.1.1.1) if version 1.2 exists, and a get -e on version
1.2.1.1 will result in a branch (1.2.2.1) if version 1.2.1.2 exists.
If the "enable branches" flag is set, it is also possible to make
branches for revisions that do not have successors. This is done with
the -b flag of get.
Keyword substitution is performed unless the -k option or the
-e option is given to get.
what contains a keyword substitution example.
The keywords are all of the form %x% where x stands for
an upper-case letter, one of:
%Z% %Y% %M% %I% %Z%.
s.foo.c.
m (module) flag, or the base name
of the SCCS file with the s. removed if the module flag is
unset.
q flag. The q flag has no other purpose, and
can be set with admin -fqfoo-w
flag, if given.
t (module type) flag.
@(#). See what.
Some of the keywords listed above have expansions that are described
in terms of the contents of other keywords. This expansion is
performed as if the y flag in the SCCS file is not set.
For example, admin -fyA will cause the %I% keyword not
to be expanded, but the %A% keyword is still fully expanded,
even though it is defined in terms of %I%.
This section describes how included, excluded and ignored deltas are handled by CSSC. Little documentation is available on how SCCS handles this, and so while this section describes how CSSC works, it may in fact not be an accurate description of how CSSC should work.
If you spot a defect in this section (or of course any other section) of the CSSC manual, please report this as a bug (see Problems).
The usual case is where none of the deltas in the SCCS file has any included, excluded or ignored deltas. All the lines in the body of the SCCS file are there because they were first inserted by a particular delta. All of these lines are copied through to the gotten file, unless they are deleted by a later delta. For example if an SCCS file contains deltas 1.1 and 1.2, then all the lines from delta 1.2 will be included, and all the lines from delta 1.1 which are not deteled in version 1.2 are also included.
Normally the contents of the gotten delta is included in the output, along with all the non-deleted lines of its ancestors. However, a delta can also specify that some other delta should be included. This really only makes a difference when there is a branch in the file.
For example, if delta 1.5 includes 1.3.1.5, then the gotten file will include the contents of versions 1.1 through to 1.5, plus the contents of the 1.3.1 branch up to and including 1.3.1.5. Lines which were (say) added in 1.2 but delted in 1.3.1.1 will not appear in the output, since we have included a delta that deletes them.
Excluding a delta is, unsurprisingly, more or less the opposite of including one. The exclusion of a delta supercedes the inclusion of a delta. One might specify, for example, that delta 1.6 should exclude delta 1.5 (for example to back out of any changes it made). Exclusion can also be used to reverse the effect of an inclusion. Suppose that delta 1.6 in the example from the section above excludes 1.3.1.5, then 1.6 will include the contents of deltas 1.1 through to 1.4, plus the contents of delta 1.5 itself, but it will not include the data from the 1.3.1 branch that would have been used if we had gotten delta 1.5.
Ignored deltas are "silent"; that is, lines which are added by a delta which is (explicitly or implcitly) included will not appear in the gotten file. Conversely, lines deleted by an ignored delta will still appear in the gotten file.
helpThis module is not implemented, and it probably will never be, because
it exists to translate the sometimes obscure error messages produced by
(genuine) SCCS. These messages come with identifying codes (like
"(ge4)"); one might type help ge4 to translate an obscure
message into a more readable message detailing what has gone wrong. The
problem with this approach is that it results in a program called
help on the user's path. When a naive user types help they
are probably not looking for an explanation of an obscure message from
SCCS. In fact, help is in any case a shell builtin for GNU
Bash. Explanations of any obscure or unusual error messages belong in
this manual, and so no sccs-help program is provided or planned.
prsThe prs command (mnemonic: "print revision summary") prints
information about an SCCS file in a user-defined format. There are
options for selecting which deltas are reported on; selection is
possible by check-in time or by SID. The format of the output can
also be specified on the command line. All parts of an SCCS file
can be dumped with prs. Those parts which appear once per delta
can be uniquely identified by SID or by time.
Typical uses for prs are
get -m command is also useful for
this, see Options for get.
prsHere are some examples of the use of prs, with explanations of what they do.
prs s.myfile.c
myfile.c.
prs SCCS
SCCS.
prs -e -d:P: s.main.c | sort -u
prs -l -c`date +%y%m%d --date "last week"` SCCS
SCCS. Show any deltas
that have been created since last week.
prs-a
-c[cc]YYMMDDHHMMSSprs is the last one checked in before the
cutoff. As usual, any fields left unspecified in the cutoff are given
the maximum legal value (for example, the seconds field defaults to 59).
The fields can be separated by any non-numeric character, for example
-c97/11/02-11:25:42.
As an extension specific to CSSC, if the argument contains more
than twelve (12) digits, and the first four characters are all digits,
it is assumed that a four-digit year form has been used. This means
that you can say -c1997/11/02-11:25:42 to mean the same as the
above.
In line with the X/Open CAE Specification, Commands and Utilities (version 2, September 1994, pages 588 and 361), if the century field is not given and the year is less than 69, it is assumed to be a year in the twenty-first century. The X/Open document does not mandate a four-digit year specifier, but it would not make sense to apply this rule if a four-digit year is specified. See Year 2000 Issues.
This behaviour is usually not the one required, and hence the -e
or -l options are specified too.
-dformatIf one specifies the -d option, prs by default only gives
information about the latest delta. To restore the default behavior of
showing all the deltas, use the -e option as well.
-e
-c option select deltas created at or earlier than the
specified time. Makes the -r option select deltas before and
including the one specified by the indicated SID.
-l
-e option, but select only later deltas rather than
earlier ones.
-rSID-d option of prsThese keywords expand to the same thing, no matter which version is being examined. Many of these are SCCS file flags (see Flags).
:BD:
-b option of prt (see prt options).
:BF:
yes or no) of the branch flag.
:CB:
:Ds:
:F:
:FB:
:FD:
:FL:
:J:
yes or no) of the joint-edit flag.
:KF:
yes or no) of the keyword-warning flag (see admin).
:LK:
:M:
m flag).
:MF:
yes or no) of the MR validation flag
(see delta).
:MP:
:ND:
n) flag (yes or no).
:Q:
:PN:
:UN:
-a and
-e of admin; if this list is empty, any user is
allowed to use delta on this file (subject to the usual file
permissions checks made by the operating system). However, in this
case the UN data keyword somewhat curiously expands to
none.
:Y:
The :BD:, :FD:, :FL: and :UN: keywords from
this section may expand to strings containing newlines.
These keywords expand to data that is specific to a particular version.
:A:
:Z::Y: :M: :I::Z:, useful for what.
:B:
:C:
:D:
:Dy:/:Dm:/:Dd:. The year is always represented as two digits but
is not ambiguous since the two-digit year is no later than 2068
(see Year 2000 Issues).
:Dd:
:Dg:
:DI:
:Dn:/:Dx:/:Dg: (sequence numbers
included/excluded/ignored).
:DL:
:Li:/:Ld:/:Lu: (lines inserted/deleted/unchanged).
:Dm:
:Dn:
:DP:
:DS:
:Dt:
:DT: :I: :D: :T: :P: :DS: :DP:.
:DT:
R (removed) or D (normal).
:Dx:
:Dy:
:GB:
:BD:. Keyword expansion will be performed
in the same way as if get had been used.
:I:
:L:
:Ld:
:Li:
:Lu:
:MR:
:P:
:R:
:S:
:T:
:Th:::Tm:::Ts:).
:Th:
:T:).
:Tm:
:T:).
:Ts:
:T:).
:W:
:Z::M:<TAB>:I:, suitable for what
(see what).
:Z:
@(#) (see what).
The :C:, :GB: and :MR: keywords from this section
may expand to strings containing newlines.
prtThe prt command provides information about an SCCS file
without modifying it. There are many options, though the default
behaviour is usually appropriate. It is possible to select what
revisions to print information on, by SID or by date.
Some SCCS implementations lack the prt command, though
none lack the prs command (see prs) which is otherwise
quite similar.
prtThe output provided by prt when no options are given is
sufficient most of the time, and so it's common to use it without any
options:-
prt s.umsp.c
If you require more detail, the -e ("everything") option
produces more detail:-
prt -e s.umsp.c
As usual, any argument that is the name of a directory causes all
SCCS files in that directory to be processed; the special argument
- indicates that a list of SCCS files are to be read from
prt's standard input.
prt-a
rmdel has been used to remove
a delta.
-b
^A (Control-A, ASCII code 1) which
starts some lines of an SCCS file is printed as three asterisks,
***. Lines that do not start with the control character are
indented by one tab stop. For encoded (binary) files, the encoded form
of the file data is printed (this is what actually appears in the
SCCS file itself). If you want to extract the actual body of the
SCCS file, use the :BD: keyword of prs (see Data Keywords.
-d
-b, -f, -t and -u flags, but
specifying -d on the command line again will ensure that the
delta information is printed.
-e
-i -u -f -t -d.
-c[cc]YYMMDDHHMMSSprt stops printing delta information when it reaches a SID
at least as old as the cutoff. As usual, any fields left unspecified in
the cutoff are given the maximum legal value (for example, the seconds
field defaults to 59). The fields can be separated by any non-numeric
character, for example -c97/11/02-11:25:42.
As an extension specific to CSSC, if the argument contains more
than twelve (12) digits, and the first four characters are all digits,
it is assumed that a four-digit year form has been used. This means
that you can say -c1997/11/02-11:25:42 to mean the same as the
above.
In line with the X/Open CAE Specification, Commands and Utilities (version 2, September 1994, pages 588 and 361), if the century field is not given and the year is less than 69, it is assumed to be a year in the twenty-first century. The X/Open document does not mandate a four-digit year specifier, but it would not make sense to apply this rule if a four-digit year is specified. See Year 2000 Issues.
The -c and -r options are mutually exclusive.
-f
-i
-r[cc]YYMMDDHHMMSS-c option, but with the opposite
sense; that is, nothing is printed for deltas that are more recent than
the indicated time.
The -c and -r options are mutually exclusive.
-s
-t
admin
-t (see admin).
-u
-ySID-y, the most recent delta is selected. The oder in which delta
information is stored within the SCCS file is such that the
SID selected by this option will be the last one printed.
If the -y option is used in conjunction with either the -c
or the -Y option, processing stops when either condition (date or
SID match) is satisfied.
prt output formatThe output format is fixed, though parts of the output can be omitted.
-d, -e, also the default,
but not if -b, -f, -t, -u are specified).
This section is printed once for each selected delta.
This begins with a newline as a separator (except when a cutoff is being used, in which case the SCCS file name is used, followed by a colon and a TAB character).
inserted/deleted/unchanged. These
statistics are capped at 99999, due to a limitation in the file
format.
-s option has been specified.
everyone is printed)
-t option of admin).
^A that begins some lines is
printed as *** , and other lines are printed indented
by one tab stop. Other than that, the body is printed as found
in the SCCS file. This means that binary files are left
encoded.
rmdelThe rmdel ("Remove Delta") command allows the last version last
checked in to an SCCS file to be removed again. Typically, one
does this after realizing that newly checked in version doesn't compile,
or doesn't work, and the fix is simple. In the author's opinion, it's
almost always better to be honest about mistakes, and just make a new
delta for the fixed version.
The SID of a removed delta is soon re-used by delta, usually
for the fixed version.
The rmdel command takes only one option, -r, which
specifies the SID of the version to be removed. This option is
mandatory.
The rmdel command will fail if you hadn't checked in that
revision, or if it is in use in some way. For example, rmdel
fails if the specified SID is not the latest revision on its
branch, or if it has been checked out for editing.
As usual, any number of SCCS files can be named on the command
line. The special argument - indicates that the list of files to
be operated on should be read from standard input. If an argument is a
directory, the RMDEL command is applied to all SCCS files in
that directory.
sactThe sact ("Show Editing Activity") command provides
a summary of which files are currently checked out for editing.
For each checked-out file, a summary line is given. This line is of
the form old-SID new-SID user date time.
old-SID
new-SID
delta when the
working file is checked in again.
user
date time
No output is produced for SCCS files that are not currently locked
for editing. If a directory is specified on the command line, the whole
directory is examined. Directory hierarchies are not descended beyond
this one level. If - is given as an argument, filenames are read
from standard input.
Note that times in SCCS files (and lock-files) are stored as local time, so if you are collaborating with developers in another time zone, the date shown will be in their local time for files that they are editing.
sccsThe sccs utility is available with CSSC. The code has
been adapted to support GNU Autoconf, but it should function in the same
way. The only difference between the operation of the original BSD
sccs program and that of the one provided by CSSC is that
way that the called programs are searched for. While the original
program has the paths hard-coded in as /usr/sccs/*, the version
accompanying CSSC first searches for them on the PATH, and then
falls back on /usr/sccs/*. If the executable is running
set-user-id, the PATH environment variable is ignored. The
sccs program itself should be fairly secure, but the other
programs in the suite are not. See Known Problems, for more
information.
The sccs program is documented in its online manual page, and
also in An Introduction to the Source Code Control System by Eric
Allman, a copy of which is included with this suite.
Unlike all the other parts of the suite, the sccs program and its
accompanying documentation are covered by the BSD copyright license; see
BSD Code, and the file COPYING.bsd, for more information.
The original BSD version of the sccs program can easily be found
on BSD mirrors, for example ftp://ftp.freebsd.org/.
sccsdiffThe sccsdiff command compares two revisions stored in an
SCCS file, using the system utility diff. Options can be
passed on to diff, for example to set the output format. As with
the other utilities in the suite, sccsdiff will operate on a list
of s-files, but unlike most of the others, it will not process
directories named on the command line.
If you wish to compare the working copy of a file with a version stored
in the s-file, you should use the command sccs diffs
(see sccs).
The options for sccsdiff are described below.
--help
--version
sccsdiff program.
-p
-rSID
All other options not appearing above are passed on to the diff
program. All the non-option arguments will be processed in turn as
SCCS files.
ungetThe unget command is used to reverse the effect of get
-e. Typically you might do this when you embark on an edit of a
file, and it all goes horribly wrong. Using unget allows you to
revert to a previously-known state. In fact, if you have exercised some
care in checking in new revisions, perhaps using a test suite, then
unget can be used to return you to the last working version.
unget-n
-s
-rsidvalThe val command is used to validate a (possibly suspect)
SCCS file. If an SCCS command reports that the checksum of
an SCCS file is incorrect, this may mean that the file has been
corrupted. In this case, val may help to confirm this
(but see Why val doesn't solve the whole problem).
Example usages:-
val s.foo
val -mfoo s.foo
val -r1.2 s.foo
val s.foo s.bar SCCS/s.*
val /proj/python/spam/spam/eggs/spam
val-mname-s
-V
-rwanted-ytypeSome possible problems with SCCS files are not definitively
errors. In these situations, val will emit a warning message
but the validation will not fail (that is, if there are no other
problems the return value will be zero). An explanation of the
possible warnings appears below.
Some versions of SCCS, but not CSSC exhibit a peculiar
behaviour in these circumstances, and do not include in the gotten
file any lines apparently inserted after the date of the delta which
has been selected. This applies to get but more importantly
also applies to the temporary file generated by DELTA which is
compared with the working copy of tyhe file. Once this has happened
there is no way to recover from this problem other than to hand-edit
the SCCS file.
y flag of the SCCS file
is set to a value which includes a keyword letter which is not known.
This is harmless unless you intended to set the flag to some other value.
Flags.
The value returned by the val program depends on the outcome of
the validation as follows :-
-m option was used but the module name did not match.
-y option was used but the module type did not match.
-r option was used but the specified SID was ambiguous, or
not present in the history file.
-r option was used but the specified SID was invalid.
Things that paranoid people might bear in mind are
val concludes that a history file is structurally valid,
this does not mean that the file contains what you thought it did (for
example, perhaps the file was corrupted by having another, valid,
SCCS file copied over it, or perhaps it was overwritten by an old
backup version).
Things that an optimistic person might bear in mind are
val does are very small indeed.
val performs are done anyway (CSSC differs slightly in this
respect from the traditional SCCS toolset).
The summary is that it is theoretically possible to fool the integrity
checks performed by the SCCS file checksum and by val but
the checksum isn't fooled often and the chances of fooling both
together are very small. The use of quality hardware reduces the
chance of data corruption yet further.
whatThe what program is designed to search in files for the
recognition string @(#). All the strings it finds matching this
are printed on standard output.
The exit status of what if zero is a matching string as found,
and 1 otherwise.
whatwhat [-s] [-V] file [file ...]
-s
-V
what.
While the file is being edited (either at first or after get -e):-
#ifndef CONFIG_NO_SCCS_IDS
static const char sccs_id[] = "%W%";
#endif
When the file is checked out for compiling (with get):-
#ifndef CONFIG_NO_SCCS_IDS
static const char sccs_id[] = "@(#)foo.c 1.3";
#endif
After compiling:-
$ what foo
foo:
foo.c 1.3
If the executable is linked from several source files, you will get a
line of output for each string containing the identification string
@(#). This is useful for finding out exactly what code went into
an executable. This technique also works on object files, archive
libraries, text files, and in fact any sorts of files at all.
Unlike the strings command, there is no way to make what
operate on standard input. The data would need to be written to a file
first.
The rationale for the preprocessor construct CONFIG_NO_SCCS_IDS
is that sometimes compilers or lint-pickers complain that the variable
sccs_id is unused, and defining CONFIG_NO_SCCS_IDS will
remove these IDs and thus silence the warnings.
Temporary files are used during normal operation of CSSC (and SCCS). Many of these are given fixed names. The prefixes for the various files used by CSSC are listed in the table below.
s.
p.
z.
x.
q.
d.
diff in this file instead.
u.
All of the temporary files in the above table are created in the same directory as the s-file, rather than in the current working directory.
Since these filenames are always fixed, it is important that the permissions on the directory containing the SCCS file be secure; otherwise you have a security vulnerability where a malicious user can cause you to accidentally over-write files you own or have access to, but they do not. If you are the super-user, they can use this feature to overwrite any file on the system.
This chapter provides a description of the format of SCCS files. It is not authoritative, and may not match some of the peculiarities of your vendor's implementation.
An SCCS file contains two parts, the header and the body. The header contains information about both the file as a whole and also information about each version stored in the file. After this comes the body itself, which is a stream of fragments from the controlled file interspersed with control information which indicates which versions these fragments appear in.
Most of the control information for SCCS files appears on lines
which are marked as special by the character whose value is 1 (ASCII
SOH); this is usually referred to as ^A. Lines in SCCS
files always end with a line feed (ASCII LF) rather than a carriage
return (ASCII CR) followed by a line feed.
There are several parts to the SCCS file header:-
The first line of an SCCS file contains the checksum, preceded by
^Ah. The checksum is in decimal and is generated by adding
together the values of all the characters in the file, and taking the
result modulo 65536. A checksum line might look like this:-
^Ah36650
On systems whose C implementation considers the char type to be
unsigned, characters with their highest bit set appear to be considered
positive, and on machines with a signed char type, these
characters appear to be considered negative. This seems to mean that
these two types of machines will not agree on the correctness of an
SCCS file's checksum.
The BitKeeper suite uses ^AH to introduce its checksum
line rather than ^Ah, but the checksum is computed in the same
way.
The checksum is followed by the delta table. Each entry describes one version stored in the history file, and is composed of three lines plus some comment lines. The first line introduces a new delta table entry and has the form
^As 00001/00000/00010
The three numbers represent the numbers of lines inserted, deleted and unchanged in this version (with respect to its predecessor). For the oldest version in the history file, the numbers of lines deleted and unchanged should be zero and the number of lines inserted is the number of lines in the initial version of the working file. These numbers are always five digits long. If the true count of inserted, deleted or unchanged lines is greater than 99999, then the fields will still only contain 99999.
The second line has the form
^AD 1.5 68/12/31 23:59:59 james 5 4
Here, the D indicates that this is a normal delta. The only
other type of delta is the removed delta. Removed deltas are created
with the rmdel program and are labelled with an R instead
of a D. This is followed by the SID, which will have either
two or four fields separated by a decimal point (ASCII code 46 decimal).
A SID with only two fields (release and level) is said to be on the
trunk of the revision tree. A SID with the full four fields (the
last two are the branch number and the sequence number) is said to be a
"branch revision". Each field in the SID, if present, must
contain a positive integer no larger than 9999. This means that
1.0 would not be a valid version number, for example.
The third and fourth fields on this line are the date and time at which this delta was added to the history file (rather than, for example, the modification time of the working file which was checked in). The year is represented with only two digits, and is deemed to be in the range 1969 to 2068 (see Year 2000 Issues). Despite having only two year digits, the date is in ISO order (year/month/day). The time is indicated using 24-hour clock notation. The date in the above example is the latest date it is possible to represent in an SCCS file.
The fifth field is the name of the user who checked this version in. For the gratification of pedants, it should be noted that this is the name associated with the actual user-id rather than the effective user-id, or the name appearing in the system log as the user who logged in on the controlling terminal.
The final two fields are called delta sequence numbers, or
seqnos. They are for the internal use of the implementation and
should not be confused with "sequence numbers", which are the final
fields of four-field ("branch") SIDS. The seqno of the delta
added last will be larger than that of any other delta. Each delta has
a unique seqno. The first of these two fields is the seqno of this
delta itself, and the second field is the seqno of its predecessor (that
is, the version which had been checked out with get -e). The
seqno 0 is special and appears only as the (nonexistent) predecessor of
the first delta.
Since the delta table entries appear in reverse order of addition (i.e. new entries are always added at the top), the initial delta appears at the foot of the delta table. Many of the SCCS utilities define their cutoffs in such a way that they can stop traversing the delta table when they find a delta which is too old.
After the ^Ad line there may be several lines which indicate
lists of included, excluded or ignored sequence numbers for this delta.
I don't understand this area of the functionality of SCCS very
well, so any description here may be vague or incorrect. The CSSC
implementation may also be incomplete in this area.
The list of included seqnos is introduced with ^Ai, the
excluded seqnos with ^Ax, and ignored seqnos with ^Ag.
These are followed by a space character, and then the list itself, which
is a space-separated list of integers.
If the MR-validation flag (see Flags) was turned on at the time of the creation of this delta, one or more lines of the form
^Am mr1
^Am mr2
^Am mr3
^Am mr4
may occur. These lines constitute a list of Modification Request Numbers, one on each line.
The next part of the delta table entry is the the delta commentary.
This comment is intended to contain a description of the changes made in
this delta, and is written and read by humans. This may extend over one
or many lines, each introduced with ^Ac, like this:-
^Ac The end of the world
^Ac as we know it
If there is no comment for a particular delta, because it was suppressed
with the -y option to delta or cdc, or because the
user was presented with a prompt for comments but just typed the return
key, an empty ^Ac control line will appear at this point.
CSSC is currently slightly incorrect in this area. If the comment is
suppressed with the -y option, it emits no ^Ac lines at
all.
The BitKeeper suite uses comment lines of the form ^AcX
(where X is a non-blank character) to store data which is
specific to BitKeeper. This data is ignored by CSSC, which
provides read-only support for BitKeeper files. These special lines
are distinguished from normal comment lines by the fact that there is
no space after the c:-
^AcHathlon.transmeta.com
^AcK09043
^AcParch/arm/boot/Makefile
^AcRe1f91d8bfa21c521
^AcV4
^AcX0x821
^AcZ-08:00
Some SCCS files contain an MR list which follows rather than precedes the comments for a delta, but this is unusual.
The comment block, and in fact the whole delta table entry, is terminated by a control line of the form
^Ae
To illustrate this further, here are two more delta table entries from an SCCS file:-
^As 00001/00000/00007
^Ad D 1.2 99/12/31 23:59:59 mcvoy 2 1
^Ac Added an extra line
^Ae
^As 00007/00000/00000
^Ad D 1.1 69/01/01 00:00:00 dmr 1 0
^Ac created at the dawn of time
^Ae
Next, there is the list of authorised users, introduced by a ^Au
line. Only users in the authorised users list can modify the SCCS
file. This list always appears (though many implementations will not
complain if you remove it with an editor) but is often empty. One user
login name appears on each line. Lines can alternatively contain
numbers, denoting whole groups of users (as listed in /etc/group
on many systems). The authorised-users list is terminated with a
^AU line. Some broken implementations emit lines of the form
^AU 0 here instead; the polite thing to do is to ignore gaffes of
this sort. This is of course what CSSC does.
The file flags section occurs after the authorised-users list. Each file flag occurs on a separate line and are possibly followed by their values (except the boolean flags, whose mere presence is sufficient). These lines look like this:-
^Af f e 0
^Af f n
^Af f q Q-flag-value
^Af f v /bin/true
The e flag, if set to a nonzero value, indicates that the
controlled file is binary and is therefore stored in uuencoded form in
the file body. If this flag is set to zero or is missing, then the file
body is not encoded. See Flags for information about the other
possible flag letters and their meanings. See Interoperability
for information about sharing SCCS files with other implementations
of SCCS.
The e flag is a boolean flag but is stored within the SCCS
file with a value, as shown in the example above. When CSSC
initially writes the SCCS file header for a new SCCS fiel
created with admin -i, it does not know if the initial body of
the file is binary or not, so ^Af f e 0 is written into the
header and if the file turns out to need encoding, admin will
seek back to the header and change ^Af f e 0 to ^Af f e
1. If binary file support is disabled (see Binary File Support,
^Af f e 0 is still used but will never be changed to ^Af
f e 1.
The value for the y flag is stored as a space-separated list of
keyword letters, even though the letters were separated by commas when
they were passed to admin -fy. This flag is an extension
introduced by Sun Solaris 8. See Interoperability for a
discussion of the interoperability of CSSC with other SCCS
implementations.
The flags section is followed by the descriptive text for the history
file. This section is intended to contain text which might contain a
copyright statement, or might indicate the purpose of a file or
contain special instructions, and so on. This section starts with a
^At control line and is terminated with a ^AT control
line:-
^At
This is the blah blah...
... blah.
^AT
The ^AT control line marks the end of the SCCS file's
header. The following line is the first line of the file body.
This example also includes the file body, since the body is short.
^Ah38213
^As 00002/00000/00000
^Ad D 1.3 98/11/22 18:25:43 james 3 2
^Ax 2
^Am 99
^Ac This delta was produced using "get -e -x1.2 s.foo" and
^Ac then "delta s.foo".
^Ae
^As 00001/00000/00000
^Ad D 1.2 98/11/22 18:22:56 james 2 1
^Am mr1
^Am mr2
^Am
^Ac comment goes here.
^Ae
^As 00000/00000/00000
^Ad D 1.1 98/11/22 18:21:11 james 1 0
^Ac date and time created 98/11/22 18:21:11 by james
^Ae
^Au
^AU
^Af e 0
^Af n
^Af q UMSP
^Af v /bin/true
^At
Descriptive text
^AT
^AI 3
this delta was made from a working file which was gotten for editing
but excluded the delta named 1.2.
^AE 3
^AI 2
blurg
^AE 2
^AI 1
^AE 1
The body of an SCCS file is usually much longer than its header,
but contains fewer ingredients. It contains control lines, which signal
the beginning or end of a chunk of user data, and the user data itself.
If, for example, you added the text I was here to the controlled
file as a delta whose delta sequence number was 7, the history might
contain these lines:-
^AI 7
I was here
^AE 7
I currently have no clear understanding of the interaction of excluded,
included or excluded revisions with the normal check-in processing.
Hence I can't thoroughly explain the precise meaning of the ^AI,
^AE and ^AD control lines. This section will be completed
at a future date. If you have an understanding of these issues, please
let me (jay@gnu.org) know.
This part of the CSSC manual describes how CSSC interoperates with SCCS. For the enormous majority of cases, this occurs seamlessly; however sometimes it is not possible for CSSC to pick "one right way" to proceed unaided. Circumstances where this occurs are described in detail, below.
In order to interoperate better with other implementations of SCCS, the CSSC suite can also be configured to turn off several features which provide flexibility beyond that which is available in some other implementations of SCCS. Some other interoperability features of CSSC exist to maintain compatibility but do not need to be turned off.
Binary file support can be turned off when you run "configure" by
specifying the --disable-binary option. This will cause
admin to refuse to create an SCCS file whose "e" flag is set
(see Flags). The admin program would normally do this if the
user requested it via the -b option or if it discovered that the
file could not safely be stored in the normal SCCS file format.
This setting can be overridden with the environment variable
CSSC_BINARY_SUPPORT; for a description of how to use this
environment variable, see Environment.
If you use CSSC with support for encoded SCCS files turned off, encoded files will still be handled; CSSC will just refuse to create a new one. This provides as great a degree of interoperability with other implementations of SCCS as possible.
The support that CSSC provides for binary files allows the controlled file to contain any sequence of bytes. That doesn't imply that the controlled file is used for any particular purpose. For example, JPEG files can contain non-ASCII acharacters.
This should be contrasted with support for executable files,
which have a specific Unix file mode bit set (see the manual page for
chmod for more details). Unix executable files may or may not
be binary files. It's common to control shell scripts with
CSSC, for example. Shell scripts are normaly executable but not
binary.
If the x flag is set, CSSC will generate a g-file whose
execute bits are set. This feature exists for compatibility with SCO
OpenServer's SCCS. Do not use this feature if you wish to
interoperate with other implementations of SCCS. Setting this
flag with admin -fx generates a warning about this.
Read-only support is provided for files produced by the BitKeeper suite. Flags and information which are specific to BitKeeper is ignored by CSSC. At the moment, it is not possible to turn off support for BitKeeper files, but a warning message is issued when one is encountered.
Actions on BitKeeper files that CSSC will not perform include
CSSC does not prevent the use of unget on BitKeeper files,
because unget does not examine the SCCS file header (and
therefore has no way to determine if the file is a BitKeeper file or
not).
By default, CSSC enforces no line length limits. The CSSC tools
will correctly process input files containing lines of arbitrary
length, subject to the limits of available memory. The system command
diff may impose its own limit however; this is discussed below
(see Limitations of diff).
If you are working with a binary file (that is, the -b option
to admin was used when the history file was created), the
encoding mechanism used by CSSC (and those SCCS
implementations that support binary files) ensures that data is
encoded before being stored in the body of the history file, and so
the "binary" file can contain any sequence of bytes at all - the
"line length" is no longer important.
Most other implementations of SCCS do however have an upper limit
on the maximum length of line that can be handled in a text file (that
is, those versions of SCCS which have such a limit do not apply
this limit for binary files). To set such a limit in CSSC, use
the --enable-max-line-length=N option to "configure". This
sets the limit to the specified value.
This setting can be overridden with the environment variable
CSSC_MAX_LINE_LENGTH; for a description of how to use this
environment variable, see Environment. To determine the current
setting of the line length limit, run admin -V and read the
output.
If (and only if) you have configured CSSC with such a maximum line length limitation, the lengths of input lines are checked as they are being read. When CSSC is adding a new delta to an existing file, if it finds an input line which is longer than N characters, it will fail with an explanatory message (the alternative would be that an SCCS file would be generated that could not be read by other implementations of SCCS having a lower line length limit).
When CSSC is creating a new SCCS file in response to the
admin -i command, one of two things will happen when an
over-length line is found. If binary file support is enabled, the
SCCS file will automatically be created as an encoded file.
Otherwise, admin will fail with an explanatory message.
When the CSSC tools are reading a history file, the lines in the
SCCS file are not subject to the limits described above; that is,
CSSC imposes these limits on lines it puts into the
SCCS file, but not on lines it reads from the SCCS
file. This means that the CSSC get utility will cope with
arbitrarily long lines in the SCCS file, even if CSSC has
been configured in sauch a way that delta would not put such
long lines into the history file.
The diff utility may have limits on the lengths of lines that
it can process, though the GNU diff program has no such limits.
This means that if you are using CSSC in combination with a
diff which has a line length limit, that limit will apply to
the operation of the CSSC delta and sccsdiff
programs (though not to any other component of CSSC).
This kind of problem may cause delta to fail because the file
you are checking in contains an over-length line. However, because
SCCS files may be operated on by SCCS implementations that
have different upper limits, you might also find that the delta you
checked out from the history file already contained a line which is
longer than can be coped with by your delta utility. GNU
CSSC can always be switched back a mode in which there is no line
length limit (i.e. the mode which is usually the default) and so can
be used to work around such situations.
Bear in mind that implementations of diff and SCCS on a
given system can have different limits on the sizes of lines
that can be handled by delta, get and diff. This
is not the case with the GNU system however, which has no such limits.
The diff utility will also fail if the last line in one of the
files being compared does not end in a newline. To work around this
you can either encode the file as a binary file (see admin) or add
a terminating newline (which is usually the best course of action).
The diff program to be used by the CSSC tools is selected
when the configure script is run, before CSSC is compiled.
Configuration explains how you can determine which diff command
is used by CSSC.
To discover how a particular installation of CSSC is configured,
pass the -V option to any of the CSSC tools. The
"configure" script defaults to not limiting the maximum line length,
but you must specifically indicate if binary file support is to be
enabled or not when running "configure".
Some other implementations of SCCS have bugs, too. Where we know about these and can work around them, we do this. Please not that these bugs only affect some other versions of SCCS - if they affected all versions, they'd be the correct behaviour of CSSC too!
There are some features of SCCS implementations with which CSSC cannot maintain compatibility.
This section outlines some of the ways in which various versions of SCCS differ from each other and therefore sometimes from CSSC.
The various versions of SCCS differ in their level of support for binary files (see Binary File Support), and in the maximum line length that they will support (see Maximum Line Length.
There are some small variations in the way that the several versions
of sccsdiff behave. These are outlined in the table below :-
diff output for each
s-file. This separator is output before the first set of diff output,
even if only one s-file has been named on the command line.
There are a few differences in the behaviour of the admin
command across the various SCCS Implementations :-
-n option
-n option
without the -i option. A workaround is to use -n
-i/dev/null instead.
-b
option to admin. See Binary File Support, for more
information.
x
flag, which turns on the executable bits of the mode of the g-file
when it is created. Other versions of SCCS do not have this
feature. While CSSSC provides this feature also, its use is not
recommended. The prt -f command does not indicate the value of
the x flag.
-r option is used to specify the release of the initial
delta. Some implementations of SCCS allow this to be used to
specify more components of a SID than just the release number.
The CSSC version of admin allows this usage but issues a
warning message. If the -r option is used to specify a
non-trunk SID (that is, a SID with more than two
components), this is allowed but some of the other tools in the
CSSC suite will not work correctly on the resulting file.
If the "encoded" flag is set, some versions of prt (but not
the CSSC version) omit a newline in the output and so the next
thing follows immediately on the same line.
Sun Solaris 8 features a y flag. If the y flag is set
in the SCCS file, only the specified SCCS keywords will be
expanded in the gotten file (assuming that the -k and
-e options are not used).
The get command on SCO OpenServer honours the setting of the
x flag. This is described above.
For a discussion of the interoperability of CSSC with other
SCCS implementations, see Interoperability. For a
description of the x and y flags, see Flags.
There are some respects in which CSSC behaves unlike other versions of SCCS. These differences mainly relate to the removal of arbitrary limits or problems, and generally do not pose an interoperability problem. The most important extensions are listed below.
-c option to get supports four-digit years.
See The Good News.
admin -i, the
admin command will automatically determine if the file needs to
be encoded. Other versions of SCCS which do this rely on being
able to seek in the input file specified as the argument to the
-i option, which means that this is not possible if the
initial file body is being read by a pipe. The CSSC
implementation of admin does not have this limitation, since it
seeks on the file being created instead. See Unemulated Features.
x and y flags and binary file encoding). The
CSSC suite attempts to honour all of these extensions, and is
probably the only implementation which has all these features. If you
try to use a feature which is specific to only one implementation of
SCCS, CSSC will issue a warning that what you are doing is
not portable.
If you use features of CSSC which are extensions originating in
more than one other SCCS implementation, for example both the
x and the y flags, you have effectively tied yourself to
CSSC. Once you are in that position, you are no longer able to
interoperate with any other version of SCCS (since, in this
example, any other version of SCCS will fail to understand either
the x or the y flag). If interoperability with other
versions of SCCS is no longer an issue, you might as well bite
the bullet and migrate to a more modern configuration control system
entirely. See Overview.
val implements some checks that
other implementations lack. Howver, it is not complete, and so there
are also checks that other implementations make that CSSC does
not.
(ge4).
/dev/null. This prevents error
messages going into a file opened by CSSC for writing (for
example an SCCS file).
prt and get will still work).
diff and the MR-validator specified by the v flag.
However, with the exception of the sccsdiff shell script, the
tools within the CSSC suite do not invoke each other. For
example, delta does not invoke get. This behaviour is
different to the traditional architecture of SCCS and might
introduce subtle differences of behaviour. Any such differences are
bugs; see Reporting Bugs.
See also Missing Features and other Problems.
Several environment variables control the behaviour of CSSC. This section explains what these variables are and how they work.
Unlike some other implementations of SCCS, CSSC tools do not
usually execute each other. This means for example that delta
does not invoke get to extract the previous version of the file,
and prs doesn't use get when processing the :GB:
keyword.
There are a small number of exceptions to this rule :-
sccs
sccs driver program can be used to invoke any of the other
tools in the suite. See Known Problems, for a discussion of the
issues this raises.
delta
delta program runs a program to validate the Modification
Request Numbers offered by the user. See Modification Request Numbers.
sccsdiff
sccsdiff program is a shell script, and invokes
get, diff and pr, as well as other tools such as
cat, test and rm. The sccsdiff program must
not be installed set-user-id.
The driver program sccs takes a number of precautionary steps
if it detects that it is running set-user-id or set-group-id. These
steps are described below, as part of the discussion of each
environment variable.
When "configure" is run, some default behaviours are set. These can be overridden with the use of environment variables as described below.
The CSSC_BINARY_SUPPORT environment variable controls whether
CSSC will create "encoded" SCCS files. The three valid
values for this variable are as follows :-
enabled
disabled
enabled or disabled. The default is set by
passing either --enable-binary or --disable-binary to
"configure" when CSSC is compiled. If this option was not
specified, the default value is enabled. For more information
see Interoperability.
This variable is unset by the sccs driver program, if it is
installed set-user-id or set-group-id.
The CSSC_MAX_LINE_LENGTH environment variable controls the maximum
length of lines that CSSC will allow to go into an SCCS file.
This variable should be set to a decimal integer.
The default behaviour of CSSC when this variable is unset is described in Interoperability.
This variable is unset by the sccs driver program, if it is
installed set-user-id or set-group-id.
If "configure" detects that UIDs are not supported on the system you
are running on (that is, you are compiling on a system that doesn't look
at all like Unix) then the environment variable USER is used to
determine the invoking user's name. This is then the name which is used
in the p-file and in the delta information for new deltas. This
username is also compared against the list of authorised users by
delta. Of course, this doesn't provide much security but in the
absence of user ID support, CSSC can't tell who users really are
anyway.
The behaviour of CSSC with respect to this option is not sensitive to whether or not programs are installed set-user-id, because this variable is only consulted on systems where set-user-id is not supported. This may be a problem on systems where it is possible to grant enhanced privileges to a program, but which do not look like Unix to the "configure" program.
If set, the environment variable CSSC_SHOW_SEQSTATE will cause
CSSC to emit debugging information about the delta table to stderr.
This is only of use when debugging CSSC.
The PROJECTDIR environment variable is used only by the
sccs driver program. This variable is ignored if the the
sccs program is installed with the set-user-ID bit set. See
Known Problems, for other remarks concerning setuid execution.
The PROJECTDIR variable is used to locate the SCCS history
file corresponding to a filename given on the command line. If the
value of PROJECTDIR starts with a `/', it is used as an absolute
directory name. If PROJECTDIR does not start with a slash, it is
assumed to be the name of a user, and SCCS files are assumed to be
in the subdirectory "src" or "source" beneath their home directory.
Normally, the sccs driver program locates the other tools by
searching the directories specified in PATH, but if it is
running set-user-id or set-group-id, a compiled-in value is used
instead. By default, this value is is /usr/sccs.
If SCCS is not privileged, it will fall back on the compiled-in
value in order to find the other tools if they are not found in any of
the directories in $PATH.
In normal operation, sccs diffs will use the system diff
command by searching the PATH environment variable. This doesn't
happen if it is running set-user-id or set-group-id.
None of the programs in the CSSC suite take any specific action
regarding the LD_LIBRARY_PATH environment variable, but your
system libraries may take notice of it (or decide not to do so, for
example when a program is running set-user-id or set-group-id).
The sccsdiff program ignores the setting of the TMPDIR
environment variable. Temporary files with predictable names are
created in the /tmp directory. See Known Problems.
The sccs driver program uses the setlocale function, whose
behaviour depends on several implementation-dependent environment
variables. If you are using the GNU C library, these variables are
LC_COLLATE,
LC_CTYPE,
LC_MESSAGES,
LC_MONETARY,
LC_NUMERIC,
LC_TIME,
and
LANG. The setlocale function is not called if SCCS
is running set-user-id or set-group-id.
docs/BUGS. Once this file has
become obsolete it will be removed from the distribution.
If an item on the TODO list (see the file docs/TODO) has in
fact been fixed, this is a bug in the TODO list. Please report this via
the bug tracking system.
There are a small number of known problems documented in the files
docs/BUGS and docs/TODO. These will be fixed at some
point in the future. Future problems should be reported via the
CSSC Bug Tracker, at http://sourceforge.net/bugs/?group_id=8064.
There are also some security problems with this code:-
The sccsdiff program ignores the setting of the TMPDIR
environment variable. Temporary files with predictable names are
created in the /tmp directory.
diff command and
the program specified as the MR validation program. Some
CSSC programs (for example sccsdiff) invoke others. This
is done without "cleaning up" the environment, and so this is another
reason not to use the set-user-id bit for CSSC programs.
See Environment.
Please refer to the section of the GNU General Public License entitled "NO WARRANTY" for information regarding the lack of warranty for this program. CSSC is not a secure program, please do not rely on it to behave in a secure fashion.
Contributions of code or patches to fix these problems are, as always, gleefully welcomed. Please submit these to the maintainer.
Additionally, there is currently one problem that may not ever be fixed.
This problem occurs only in the prt program when the list of
ignored or excluded deltas is present for a SID but that list is
empty. In this case SCCS prints the Included: or
Excluded: line in its output (with no numbers afterward) and
CSSC prints nothing. Since "fixing" this problem would require a
horrible kludge, this has not been done. It is not expected that this
will cause a problem for any users; if this is a problem for you, let
the maintainer know and it will be fixed.
There are some features of (some implementations of) the traditional SCCS suite which it may not be desirable to copy.
-i option, and it turns
out to need encoding, then genuine SCCS seeks back to the start of
the file and encodes it. However, if the input file is not seekable,
for example if it is a pipe, then this doesn't always work. The
SCCS file is then sometimes created containing only the initial
part of the body, before the offending segment of the file. The exit
value of the admin program is nevertheless still zero. Tests for
this situation are in tests/binary/seeking.sh but these tests are
only carried out if the program under test seems to be CSSC rather
than the genuine SCCS suite. The CSSC suite does not have
this problem, and will always detect the need to encode the file, and
will successfully complete the process (it does not try to seek on the
input pipe).
There are also a small number of respects in which various implementations differ from each other; in such cases CSSC picks a suitable alternative; SCCS Version Differences.
Primordial (but not current) versions of the genuine SCCS suite
fail to work correctly in and after the year 2000. The commands
affected are get and prs. Unix vendors have ensured that
the version of SCCS that they currently ship works correctly in the
year 2000. Sun Microsystems, for example, state in their Year 2000 FAQ
(http://www.sun.com/y2000/faq.html)
• Does Sun see any problems with the source code control system (SCCS)?
No, Sun has adopted the X/Open Commands and Utilities Issue 5 standard, the year 2000 compliant version of SCCS will not be affected by the end of century transition. The X/Open standard states that old dates held in ("yy/mm/dd") format does not change in "s." files, but the values "yy" which range from 69 - 99 are to be interpreted as 1969 - 1999 respectively. Values of "yy" which range from 00 - 68 are to be interpreted as 2000 - 2068 respectively. This interpretation ensures that the year 2000 compliant version of SCCS will work at least to the year 2068. By implementing X/Open's standard, Sun has ensured SCCS user's compatibility with other providers of the SCCS utility. For more information please refer to: http://www.xopen.org/public/tech/base/year2000.html
Copyright © 1994 - 1997 Sun Microsystems, Inc., 901 San Antonio Road, Palo Alto, CA 94303 USA. All rights reserved.
Two-digit years are a problem in two places: firstly, within the actual SCCS files, and secondly within command-line options. The two-digit year fields in the SCCS files are correctly dealt with according to the strategy mandated by X/Open. The command-line options are also dealt with similarly.
CSSC provides an additional feature for your convenience. If the
argument to the -c option of get, prt, or
prs contains more than twelve digits, the first two are
understood to be the century part of the year. For example,
971120193000 and 19971120193000 both represent exactly the
same time (7:30 p.m. on November 20, 1997). The fields of a date can be
separated with other (non-digit) characters, and so
1997/11/20-19:30:00 also denotes the same time (but
1997/11/20 is an error because there are fewer than twelve
digits).
Some versions of SCCS are not year 2000 compliant and write incorrect timestamps into SCCS files. CSSC correctly understands the intended date, and will fix this problem when re-writing the file (see Bug-for-Bug Compatibility).
CSSC represents dates internally in a way that works for Gregorian dates up to at least the year 32767 AD on all systems. Some countries didn't recognise the Gregorian calendar system until the early twentieth century but this of course is not really a problem now. The useful life of SCCS is from 1969 until 2068. Years are stored in two-digit form in SCCS files and so although CSSC has no such limits internally, it's not possible to indicate a year outside this range in an SCCS file if you want to retain compatibility with other implementations of SCCS. All the CSSC programs will successfully work with any date in this range, all the way up to 2068, on all systems.
In this future, years after 2068 may be represented as four-digit fields, but CSSC doesn't do this yet.
The CSSC test suite (see The Test Suite) contains
some test files which may be useful in determining the date range with
which your usual SCCS implementation will cope. These are in the
directory tests/year-2000.
It's not all good news though. When new deltas are created with the
delta command, CSSC must consult the operating system to
find the current date and time. Some operating systems have a limited
range of date representation. For example, the development system I use
for most of the work on CSSC can't report any date later than
Tuesday Jan 19 03:14:07 2038 as the current time. When running on such
systems, CSSC will still be able to work with SCCS files
containing dates after this, but activities involving the current time
will not work correctly.
This date breakdown occurs most obviously with the date stamp that the
delta program gives each delta in the SCCS file, but also
with the commentary-change message of cdc and the default comment
produced by admin when an SCCS file is created.
To summarise, all reporting activities of CSSC will work correctly throughout the range of time representable in an SCCS file (that is, from 1969 to 2068 inclusive). However, commands which modify SCCS files and need to add dates may fail earlier than this (but then again, may not, depending on your operating system).
Now that you know that whatever version of SCCS you are using has probably been fixed by the vendor, and that even if your vendor's SCCS implementation cannot be updated for some reason, CSSC is Year-2000 compliant and to an extent Year-2038 compliant, I'd like you to remember the conversion effort that this has saved you. I'd also like to urge to to actually use that effort to convert your existing projects from SCCS to a more modern version control system, for example GNU CVS. There are other considerations besides Year-2000 compliance, after all. CSSC is not called "Compatibly Stupid Source Control" for nothing.
The test suite is the most important single component of the CSSC suite. It ensures that ports to new platforms are working correctly, and that changes in one part of the suite don't accidentally break anything else.
The test suites cannot cover everything. More are needed. If you only ever contribute one thing to CSSC, make it a new test case. This chapter explains how to run the test suite and also how to write new test cases.
Running the test cases is quite simple. Typically, you might do it after compiling but before installing CSSC. After running "configure", you might compile CSSC with
make
and test it with
make check
The full test suite takes just over five minutes to run on a 486 running Linux. If everything works correctly, you will see messages like:-
cd tests && make all-tests
make[1]: Entering directory `..../CSSC/compile-here/tests'
cd ../lndir && make
make[2]: Entering directory `..../CSSC/compile-here/lndir'
make[2]: `lndir' is up to date.
make[2]: Leaving directory `..../CSSC/compile-here/lndir'
../lndir/lndir ../../Master-Source/tests
../../Master-Source/tests/get:
command-names: .././common/command-names
test-common: .././common/test-common
...more messages from lndir...
/bin/sh -ec 'cd admin && for i in *.sh ; \
do \
/bin/sh $i || break; \
done'
C1...passed
C2...passed
.... more output ....
C12...passed
C13...passed
PASS comment.sh:
v1...passed
.... more output ....
b11...passed
b12...passed
PASS flags.sh:
.... more output ....
Tests passed.
make[1]: Leaving directory `..../CSSC/compile-here/tests'
If something goes wrong you will see a "FAIL" message, which looks something like this:-
C1...FAIL comment.sh C1: ../../admin -ifoo s.new.txt:
Expected return value 0, got return value 1
make[1]: *** [test-admin] Error 1
make[1]: Leaving directory `..../CSSC/compile-here/tests'
Tests failed.
make: *** [all-tests] Error 2
The thing to remember is that when you run make check, the
make program will print on the last line a message saying
"Error" only if the tests have failed.
If the test suite does indicate that the tests have failed, please submit a bug report (see Problems). Please include in your bug report
script
program invaluable for this)
If you want to run just some of the tests, there are rules in the
makefile for just running some of them. For example, the tests in the
directory tests/admin can be run with make test-admin.
Each test directory is named after one of the CSSC programs. This
indicates which program the tests concentrate on verifying. Inevitably
these tests will use more than just one CSSC program; for example,
most of the tests involve using admin to create a SCCS file
in the first place. However, the directory indicates which tool those
tests concentrate on.
If is possible for a test to neither pass or fail, but just go wrong. This can happen when the test script comes upon something that prevents the test itself working correctly, for example, because it can't remove a temporary file or uudecode a built-in sample SCCS file. When this happens you get output much like this:-
$ sh flags.sh
rm: foo: Permission denied
flags.sh: Test could not be completed
The part before the colon (flags.sh) indicates which script
could not be completed. No further tests will be attempted.
Diagnosing the problem may or may not be simple. In this case, it's
not hard; the problem is that the test suite is trying to clear away
any temporary files but it can't remove the file "foo" (because the
current directory was made read-only to force the test to miscarry, in
this contrived case). When the test suite miscarries like this and
you can't find the problem, please follow the bug-reporting procedure
(see Problems), but please indicate that it is a miscarriage in
the test suite rather than a concrete test failure.
The test cases are really just shell scripts. They are suitable for
/bin/sh on most machines. The procedure for running these is
explained in Running the tests. These shell scripts read in some
common function definitions (mostly from
tests/common/test-common) and then proceed to conduct the tests.
This section explains those commands used in the test scripts that are
not simply normal shell commands. Normal shell commands like sed
and grep are not described.
The best approach for writing new test scripts or just individual new test cases is to first think of some aspect that needs better test coverage, and then to write the test script, basing it on an existing script. To make sure that your new tests are really checking for the right things, you can run them against an existing SCCS implementation other than CSSC.
The best strategy for testing the CSSC test suite itself is to
run it against a genuine edition of SCCS, if you have one
available. Before running make check, set the environment
variable dir to point to the directory containing the programs
to be tested; this should usually be /usr/sccs.
In many implementations of SCCS, some of the tools execute others
(for example, delta often executes get to retrieve the
previous version of the controlled file). This means that to
correctly test the test suite, your PATH environment variable
should be set up to select the SCCS tools you want to test. Here
is an example of the correct way to set up the environment to test
SCCS tools in /usr/ccs/bin :-
dir=/usr/ccs/bin
PATH=/usr/ccs/bin:$PATH
export dir
make check
When you are sure that the test script is expecting the correct behaviour from programs under test, you can then run it against CSSC. After all, if you're going to set out writing your test by assuming that CSSC is correct in the area under test, of what value is the test?
The docommand function runs a specified program, and checks its
return value, standard output and error output against an expected
version. If any mismatch occurs, fail is called. The
docommand function is invoked with up to six arguments:-
docommand [--silent] label command retval stdout stderr
The docommand function normally prints the label to indicate what
stage the current test script has reached, followed by "done" when it
has finished. The --silent option turns off this behaviour, so
that if nothing goes wrong, no progress message is printed. This is
occasionally used for commands that have already been tested by a script
and are known to work, but which must be repeated several times in order
to make some other kind of test, which is yet to come. I recommend you
try to avoid using this option.
The other arguments to docommand are:-
...done.
fail will be called. If the test should not care
about the return value, use IGNORE as retval.
IGNORE as
stdout.
IGNORE as
stderr.
This command will run admin with three arguments, and expect it
to produce no output at all and return the value zero:-
docommand C5 "${admin} -ifoo -yMyComment $s" 0 "" ""
This command does something similar, but the command is expected to fail, returning 1 as its exit status:-
# We should not be able to admin -i if the s-file already exists.
docommand I7 "${admin} -ifoo $s" 1 "" IGNORE
In the example above, the error messages produced by SCCS and
CSSC are different, but both indicate the same thing. However,
since the messages are different, IGNORE is used.
The stdout and stderr arguments are processed with the
echo_nonl function, and so escape codes are valid and indeed
heavily used:-
# Test the -m (annotate SID) option with several deltas...
docommand N4 "$get -p -m $s" 0 \
"1.1\tline1\n1.1\tline2\n1.2\tline3\n" \
IGNORE
The remove function is for clearing up temporary files after
tests have finished, and for making sure that no instance of a file that
a test is supposed to create already exists before the test is made.
Typical usage is this:-
f=1test
s=s.$f
p=p.$f
remove $f $s $p
The remove function is defined as:-
remove () { rm -rf $* || miscarry Could not remove $* ; }
The success function prints a message indicating that the current
test script has passed, and exits successfully. This is always done at
the foot of a test script.
If a test fails, it is usually because one of the docommand calls
fails, and so direct calls to the fail function are rare.
However, if you do want to call this function directly, you should
supply as its argument a short description of what has gone wrong. For
example, the docommand function uses fail in the following
way:-
fail "$label: $1: Expected return value $2, got return value $rv"
The echo_nonl function outputs its argument, without a following
newline. Escape codes as for echo(1) are understood. Depending
on the actual flavour of system that the test suite is running on, this
might internally use echo -n or echo -e .....\c.
Please do not use either the -n or -e options for
echo(1) directly in test scripts, because they don't work in the
same way on all machines. The echo_nonl function is provided for
this reason; therefore, please use it. Please note also that while the
printf(1) command may seem superior, it absolutely cannot be used
because not all systems provide it.
Typical usage of echo_nonl might be:-
echo_nonl Please wait while I finish what I am doing...
# ...
echo done
The miscarry function is used to indicate that while the test
suite has not found a problem with the programs being tested, there has
been some other kind of problem that prevents further testing.
Typical usage might be:-
remove foo
echo '%M%' > foo
test `cat foo` = '%M%' || miscarry cannot create file foo.
The various implementations of SCCS vary in several different
ways, but the CSSC test suite tries very hard to pass when run
against any genuine implementation of SCCS unless it has a
definite bug. This means for example that although the CSSC
version of admin -i will support automatic switch-over to
binary mode for a file provided via stdin, and the test suite tests
this, the same property is not required of SCCS itself.
The real-thing script checks if we are actually tesing a real
implementation of SCCS. It sets the environment variable
TESTING_CSSC to true or false, depending on whether
we are testing CSSC or not.
If you are really interested in whether the implementation being
tested supports binary files or not, you should be using the
config-data script instead.
The possible non-availability of prt is another thing that the
CSSC test suite needs to know about in order to run successfully
against all working versions of SCCS. Some versions of SCCS
lack the prt program. For this reason, the tests for this tool
(in the tests/prt directory) are skipped if prt is
missing. When writing test scripts, you should never use prt
unless you are actually testing prt itself (you can almost
always use prs instead).
If your test is specifically designed to test the functionality of
prt itself on the other hand, just source need-prt
before the first test. The need-prt script will skip the
remainder of the invoking test script if prt is missing. You
might use it like this, for example :-
#! /bin/sh
. ../common/test-common
. ../common/need-prt
s=s.testfile
remove $s
docommand e1 "${prt} $s" 1 IGNORE IGNORE
success
If you find a bug in GNU CSSC, please report this via the
CSSC bug tracking system at http://sourceforge.net/projects/CSSC.
Please include the version number, which you can find by giving the
option --version to any CSSC command. Also include in
your message the output that the program produced and the output you
expected. An s. file and instructions for reproducing the error
are almost essential unless the bug is very trivial. If you are
unable to send the actual s-file itself due to confidentiality
concerns, you can mask the contents by using the script
mogrify.awk, which removes the contents of an SCCS file while
preserving its structure. You will need to use admin -z on the
result in order to correct the checksum of the transformed version of
the file. If you do this, please make sure that you
check that the problem still occurs with the transformed version of
the file.
You may also find it helpful to join the mailing list. See the file
docs/mailing-list.txt for information about the mailing list.
If you have other questions, comments or suggestions about GNU
CSSC, contact the maintainer via electronic mail to
jay@gnu.org .
Copyright © 1989, 1991 Free Software Foundation, Inc.
59 Temple Place - Suite 330, Boston, MA 02111, USA.
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
The licenses for most software are designed to take away your freedom to share and change it. By contrast, the GNU General Public License is intended to guarantee your freedom to share and change free software--to make sure the software is free for all its users. This General Public License applies to most of the Free Software Foundation's software and to any other program whose authors commit to using it. (Some other Free Software Foundation software is covered by the GNU Library General Public License instead.) You can apply it to your programs, too.
When we speak of free software, we are referring to freedom, not price. Our General Public Licenses are designed to make sure that you have the freedom to distribute copies of free software (and charge for this service if you wish), that you receive source code or can get it if you want it, that you can change the software or use pieces of it in new free programs; and that you know you can do these things.
To protect your rights, we need to make restrictions that forbid anyone to deny you these rights or to ask you to surrender the rights. These restrictions translate to certain responsibilities for you if you distribute copies of the software, or if you modify it.
For example, if you distribute copies of such a program, whether gratis or for a fee, you must give the recipients all the rights that you have. You must make sure that they, too, receive or can get the source code. And you must show them these terms so they know their rights.
We protect your rights with two steps: (1) copyright the software, and (2) offer you this license which gives you legal permission to copy, distribute and/or modify the software.
Also, for each author's protection and ours, we want to make certain that everyone understands that there is no warranty for this free software. If the software is modified by someone else and passed on, we want its recipients to know that what they have is not the original, so that any problems introduced by others will not reflect on the original authors' reputations.
Finally, any free program is threatened constantly by software patents. We wish to avoid the danger that redistributors of a free program will individually obtain patent licenses, in effect making the program proprietary. To prevent this, we have made it clear that any patent must be licensed for everyone's free use or not licensed at all.
The precise terms and conditions for copying, distribution and modification follow.
Activities other than copying, distribution and modification are not covered by this License; they are outside its scope. The act of running the Program is not restricted, and the output from the Program is covered only if its contents constitute a work based on the Program (independent of having been made by running the Program). Whether that is true depends on what the Program does.
You may charge a fee for the physical act of transferring a copy, and you may at your option offer warranty protection in exchange for a fee.
These requirements apply to the modified work as a whole. If identifiable sections of that work are not derived from the Program, and can be reasonably considered independent and separate works in themselves, then this License, and its terms, do not apply to those sections when you distribute them as separate works. But when you distribute the same sections as part of a whole which is a work based on the Program, the distribution of the whole must be on the terms of this License, whose permissions for other licensees extend to the entire whole, and thus to each and every part regardless of who wrote it.
Thus, it is not the intent of this section to claim rights or contest your rights to work written entirely by you; rather, the intent is to exercise the right to control the distribution of derivative or collective works based on the Program.
In addition, mere aggregation of another work not based on the Program with the Program (or with a work based on the Program) on a volume of a storage or distribution medium does not bring the other work under the scope of this License.
The source code for a work means the preferred form of the work for making modifications to it. For an executable work, complete source code means all the source code for all modules it contains, plus any associated interface definition files, plus the scripts used to control compilation and installation of the executable. However, as a special exception, the source code distributed need not include anything that is normally distributed (in either source or binary form) with the major components (compiler, kernel, and so on) of the operating system on which the executable runs, unless that component itself accompanies the executable.
If distribution of executable or object code is made by offering access to copy from a designated place, then offering equivalent access to copy the source code from the same place counts as distribution of the source code, even though third parties are not compelled to copy the source along with the object code.
If any portion of this section is held invalid or unenforceable under any particular circumstance, the balance of the section is intended to apply and the section as a whole is intended to apply in other circumstances.
It is not the purpose of this section to induce you to infringe any patents or other property right claims or to contest validity of any such claims; this section has the sole purpose of protecting the integrity of the free software distribution system, which is implemented by public license practices. Many people have made generous contributions to the wide range of software distributed through that system in reliance on consistent application of that system; it is up to the author/donor to decide if he or she is willing to distribute software through any other system and a licensee cannot impose that choice.
This section is intended to make thoroughly clear what is believed to be a consequence of the rest of this License.
Each version is given a distinguishing version number. If the Program specifies a version number of this License which applies to it and "any later version", you have the option of following the terms and conditions either of that version or of any later version published by the Free Software Foundation. If the Program does not specify a version number of this License, you may choose any version ever published by the Free Software Foundation.
If you develop a new program, and you want it to be of the greatest possible use to the public, the best way to achieve this is to make it free software which everyone can redistribute and change under these terms.
To do so, attach the following notices to the program. It is safest to attach them to the start of each source file to most effectively convey the exclusion of warranty; and each file should have at least the "copyright" line and a pointer to where the full notice is found.
one line to give the program's name and an idea of what it does.
Copyright (C) 19yy name of author
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
Also add information on how to contact you by electronic and paper mail.
If the program is interactive, make it output a short notice like this when it starts in an interactive mode:
Gnomovision version 69, Copyright (C) 19yy name of author
Gnomovision comes with ABSOLUTELY NO WARRANTY; for details
type `show w'. This is free software, and you are welcome
to redistribute it under certain conditions; type `show c'
for details.
The hypothetical commands show w and show c should show
the appropriate parts of the General Public License. Of course, the
commands you use may be called something other than show w and
show c; they could even be mouse-clicks or menu items--whatever
suits your program.
You should also get your employer (if you work as a programmer) or your school, if any, to sign a "copyright disclaimer" for the program, if necessary. Here is a sample; alter the names:
Yoyodyne, Inc., hereby disclaims all copyright
interest in the program `Gnomovision'
(which makes passes at compilers) written
by James Hacker.
signature of Ty Coon, 1 April 1989
Ty Coon, President of Vice
This General Public License does not permit incorporating your program into proprietary programs. If your program is a subroutine library, you may consider it more useful to permit linking proprietary applications with the library. If this is what you want to do, use the GNU Library General Public License instead of this License.
The program sccs, its source code, and its accompanying
documentation are covered by the following license:-
Copyright (C) 1998, 1999
Free Software Foundation, Inc. All rights reserved.Copyright (c) 1980, 1993
The Regents of the University of California. All rights reserved.Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
- Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
- Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
- Neither the name of the University nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
The original version of the copyright notice above dates from 1993, as
you can see. However, since that time a change has been made to the BSD
license by UCB itself. This change is described on the following letter,
which is available on the BSD FTP site in the file
README.Impt.License.Change :-
July 22, 1999To All Licensees, Distributors of Any Version of BSD:
As you know, certain of the Berkeley Software Distribution ("BSD") source code files require that further distributions of products containing all or portions of the software, acknowledge within their advertising materials that such products contain software developed by UC Berkeley and its contributors.
Specifically, the provision reads:
" * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors."Effective immediately, licensees and distributors are no longer required to include the acknowledgement within advertising materials. Accordingly, the foregoing paragraph of those BSD Unix files containing it is hereby deleted in its entirety.
William Hoskins
Director, Office of Technology Licensing
University of California, Berkeley
This change has been made to the file COPYING.bsd which
accompanies the BSD-derived code.
delta program asks for a checkin comment; this is a comment
which summarised the nature of the change which has just been made to
the file.
-x option
to get. See Options for get.
ar and tar utilities).
-g option
to delta. See Options for delta.
-i option
to get. See Options for get.
-d
option for prs. See Data Keywords for the -d option of prs.
v flag is set in the
SCCS file, you will be prompted for "MR numbers" when you check
in a new revision. These are not used internally by CSSC but may
be used to link changes to external things (for example bug report
numbers). See Options for delta.
prt and prs). These are sometimes referred to
as a "seqno" in order to distinguish them from the fourth component
of a SID.