An Introduction to the
Source Code Control System
University of California at Berkeley
This document gives a quick introduction to using the
Source Code Control System (SCCS). The presentation is
geared to programmers who are more concerned with what to do
to get a task done rather than how it works; for this reason
some of the examples are not well explained. For details of
what the magic options do, see the section on "Further
This is a working document. Please send any
comments or suggestions to eric@Berke
SCCS is a source management system. Such a system
maintains a record of versions of a system; a record is kept
with each set of changes of what the changes are, why they
were made, and who made them and when. Old versions can be
recovered, and different versions can be maintained simulta
neously. In projects with more than one person, SCCS will
insure that two people are not editing the same file at the
All versions of your program, plus the log and other
information, is kept in a file called the "s-file". There
are three major operations that can be performed on the s-
(1) Get a file for compilation (not for editing). This
operation retrieves a version of the file from the s-
file. By default, the latest version is retrieved.
This file is intended for compilation, printing, or
This is version 1.21 of this document. It was last modi
fied on 12/5/80.
An Introduction to the Source Code Control System PSD:14-1
PSD:14-2 An Introduction to the Source Code Control System
whatever; it is specifically NOT intended to be
edited or changed in any way; any changes made to a
file retrieved in this way will probably be lost.
(2) Get a file for editing. This operation also
retrieves a version of the file from the s-file, but
this file is intended to be edited and then incorpo
rated back into the s-file. Only one person may be
editing a file at one time.
(3) Merge a file back into the s-file. This is the com
panion operation to (2). A new version number is
assigned, and comments are saved explaining why this
change was made.
2. Learning the Lingo
There are a number of terms that are worth learning
before we go any farther.
The s-file is a single file that holds all the differ
ent versions of your file. The s-file is stored in differ
ential format; i.e., only the differences between versions
are stored, rather than the entire text of the new version.
This saves disk space and allows selective changes to be
removed later. Also included in the s-file is some header
information for each version, including the comments given
by the person who created the version explaining why the
changes were made.
Each set of changes to the s-file (which is approxi
mately [but not exactly!] equivalent to a version of the
file) is called a delta. Although technically a delta only
includes the changes made, in practice it is usual for each
delta to be made with respect to all the deltas that have
occurred before1. However, it is possible to get a version
of the file that has selected deltas removed out of the mid
dle of the list of changes -- equivalent to removing your
1This matches normal usage, where the previous changes
are not saved at all, so all changes are automatically based
on all other changes that have happened through history.
An Introduction to the Source Code Control System PSD:14-3
2.3. SID's (or, version numbers)
A SID (SCCS Id) is a number that represents a delta.
This is normally a two-part number consisting of a "release"
number and a "level" number. Normally the release number
stays the same, however, it is possible to move into a new
release if some major change is being made.
Since all past deltas are normally applied, the SID of
the final delta applied can be used to represent a version
number of the file as a whole.
2.4. Id keywords
When you get a version of a file with intent to compile
and install it (i.e., something other than edit it), some
special keywords are expanded inline by SCCS. These Id Key
words can be used to include the current version number or
other information into the file. All id keywords are of the
form %x%, where x is an upper case letter. For example, %I%
is the SID of the latest delta applied, %W% includes the
module name, SID, and a mark that makes it findable by a
program, and %G% is the date of the latest delta applied.
There are many others, most of which are of dubious useful
When you get a file for editing, the id keywords are
not expanded; this is so that after you put them back in to
the s-file, they will be expanded automatically on each new
version. But notice: if you were to get them expanded acci
dently, then your file would appear to be the same version
forever more, which would of course defeat the purpose.
Also, if you should install a version of the program without
expanding the id keywords, it will be impossible to tell
what version it is (since all it will have is "%W%" or what
3. Creating SCCS Files
To put source files into SCCS format, run the following
shell script from csh:
mkdir SCCS save
foreach i (*.[ch])
sccs admin -i$i $i
mv $i save/$i
This will put the named files into s-files in the subdirec
tory "SCCS" The files will be removed from the current
directory and hidden away in the directory "save", so the
next thing you will probably want to do is to get all the
files (described below). When you are convinced that SCCS
PSD:14-4 An Introduction to the Source Code Control System
has correctly created the s-files, you should remove the
If you want to have id keywords in the files, it is
best to put them in before you create the s-files. If you
do not, admin will print "No Id Keywords (cm7)", which is a
warning message only.
4. Getting Files for Compilation
To get a copy of the latest version of a file, run
sccs get prog.c
SCCS will respond:
meaning that version 1.1 was retrieved2 and that it has 87
lines. The file prog.c will be created in the current
directory. The file will be read-only to remind you that
you are not supposed to change it.
This copy of the file should not be changed, since SCCS
is unable to merge the changes back into the s-file. If you
do make changes, they will be lost the next time someone
does a get.
5. Changing Files (or, Creating Deltas)
5.1. Getting a copy to edit
To edit a source file, you must first get it, request
ing permission to edit it3:
sccs edit prog.c
The response will be the same as with get except that it
will also say:
New delta 1.2
2Actually, the SID of the final delta applied was 1.1.
3The "edit" command is equivalent to using the -e flag to
sccs get -e prog.c
Keep this in mind when reading other documentation.
An Introduction to the Source Code Control System PSD:14-5
You then edit it, using a standard text editor:
5.2. Merging the changes back into the s-file
When the desired changes are made, you can put your
changes into the SCCS file using the delta command:
sccs delta prog.c
Delta will prompt you for "comments?" before it merges
the changes in. At this prompt you should type a one-line
description of what the changes mean (more lines can be
entered by ending each line except the last with a
backslash4). Delta will then type:
saying that delta 1.2 was created, and it inserted five
lines, removed three lines, and left 84 lines unchanged5.
The prog.c file will be removed; it can be retrieved using
5.3. When to make deltas
It is probably unwise to make a delta before every
recompilation or test; otherwise, you tend to get a lot of
deltas with comments like "fixed compilation problem in pre
vious delta" or "fixed botch in 1.3". However, it is very
important to delta everything before installing a module for
general use. A good technique is to edit the files you
need, make all necessary changes and tests, compiling and
editing as often as necessary without making deltas. When
you are satisfied that you have a working version, delta
everything being edited, re-get them, and recompile every
5.4. What's going on: the info command
To find out what files where being edited, you can use:
4Yes, this is a stupid default.
5Changes to a line are counted as a line deleted and a
PSD:14-6 An Introduction to the Source Code Control System
to print out all the files being edited and other informa
tion such as the name of the user who did the edit. Also,
is nearly equivalent to the info command, except that it is
silent if nothing is being edited, and returns non-zero exit
status if anything is being edited; it can be used in an
"install" entry in a makefile to abort the install if any
thing has not been properly deltaed.
If you know that everything being edited should be
deltaed, you can use:
sccs delta `sccs tell`
The tell command is similar to info except that only the
names of files being edited are output, one per line.
All of these commands take a -b flag to ignore
"branches" (alternate versions, described later) and the -u
flag to only give files being edited by you. The -u flag
takes an optional user argument, giving only files being
edited by that user. For example,
sccs info -ujohn
gives a listing of files being edited by john.
5.5. ID keywords
Id keywords can be inserted into your file that will be
expanded automatically by get. For example, a line such as:
static char SccsId = "%W%\t%G%";
will be replaced with something like:
static char SccsId = "@(#)prog.c 1.2 08/29/80";
This tells you the name and version of the source file and
the time the delta was created. The string "@(#)" is a spe
cial string which signals the beginning of an SCCS Id key
5.5.1. The what command
To find out what version of a program is being run,
An Introduction to the Source Code Control System PSD:14-7
sccs what prog.c /usr/bin/prog
which will print all strings it finds that begin with
"@(#)". This works on all types of files, including bina
ries and libraries. For example, the above command will
output something like:
prog.c 1.2 08/29/80
prog.c 1.1 02/05/79
From this I can see that the source that I have in prog.c
will not compile into the same version as the binary in
5.5.2. Where to put id keywords
ID keywords can be inserted anywhere, including in com
ments, but Id Keywords that are compiled into the object
module are especially useful, since it lets you find out
what version of the object is being run, as well as the
source. However, there is a cost: data space is used up to
store the keywords, and on small address space machines this
may be prohibitive.
When you put id keywords into header files, it is
important that you assign them to different variables. For
example, you might use:
static char AccessSid = "%W% %G%";
in the file access.h and:
static char OpsysSid = "%W% %G%";
in the file opsys.h. Otherwise, you will get compilation
errors because "SccsId" is redefined. The problem with this
is that if the header file is included by many modules that
are loaded together, the version number of that header file
is included in the object module many times; you may find it
more to your taste to put id keywords in header files in
5.6. Keeping SID's consistent across files
With some care, it is possible to keep the SID's con
sistent in multi-file systems. The trick here is to always
edit all files at once. The changes can then be made to
whatever files are necessary and then all files (even those
not changed) are redeltaed. This can be done fairly easily
by just specifying the name of the directory that the SCCS
files are in:
PSD:14-8 An Introduction to the Source Code Control System
sccs edit SCCS
which will edit all files in that directory. To make the
sccs delta SCCS
You will be prompted for comments only once.
5.7. Creating new releases
When you want to create a new release of a program, you
can specify the release number you want to create on the
edit command. For example:
sccs edit -r2 prog.c
will cause the next delta to be in release two (that is, it
will be numbered 2.1). Future deltas will automatically be
in release two. To change the release number of an entire
sccs edit -r2 SCCS
6. Restoring Old Versions
6.1. Reverting to old versions
Suppose that after delta 1.2 was stable you made and
released a delta 1.3. But this introduced a bug, so you
made a delta 1.4 to correct it. But 1.4 was still buggy,
and you decided you wanted to go back to the old version.
You could revert to delta 1.2 by choosing the SID in a get:
sccs get -r1.2 prog.c
This will produce a version of prog.c that is delta 1.2 that
can be reinstalled so that work can proceed.
In some cases you don't know what the SID of the delta
you want is. However, you can revert to the version of the
program that was running as of a certain date by using the
-c (cutoff) flag. For example,
sccs get -c800722120000 prog.c
will retrieve whatever version was current as of July 22,
1980 at 12:00 noon. Trailing components can be stripped off
(defaulting to their highest legal value), and punctuation
can be inserted in the obvious places; for example, the
above line could be equivalently stated:
An Introduction to the Source Code Control System PSD:14-9
sccs get -c"80/07/22 12:00:00" prog.c
6.2. Selectively deleting old deltas
Suppose that you later decided that you liked the
changes in delta 1.4, but that delta 1.3 should be removed.
You could do this by excluding delta 1.3:
sccs edit -x1.3 prog.c
When delta 1.5 is made, it will include the changes made in
delta 1.4, but will exclude the changes made in delta 1.3.
You can exclude a range of deltas using a dash. For exam
ple, if you want to get rid of 1.3 and 1.4 you can use:
sccs edit -x1.3-1.4 prog.c
which will exclude all deltas from 1.3 to 1.4. Alterna
sccs edit -x1.3-1 prog.c
will exclude a range of deltas from 1.3 to the current high
est delta in release 1.
In certain cases when using -x (or -i; see below) there
will be conflicts between versions; for example, it may be
necessary to both include and delete a particular line. If
this happens, SCCS always prints out a message telling the
range of lines effected; these lines should then be examined
very carefully to see if the version SCCS got is ok.
Since each delta (in the sense of "a set of changes")
can be excluded at will, that this makes it most useful to
put each semantically distinct change into its own delta.
7. Auditing Changes
7.1. The prt command
When you created a delta, you presumably gave a reason
for the delta to the "comments?" prompt. To print out
these comments later, use:
sccs prt prog.c
This will produce a report for each delta of the SID, time
and date of creation, user who created the delta, number of
lines inserted, deleted, and unchanged, and the comments
associated with the delta. For example, the output of the
above command might be:
PSD:14-10 An Introduction to the Source Code Control System
D 1.2 80/08/29 12:35:31 bill 2 1 00005/00003/00084
removed "-q" option
D 1.1 79/02/05 00:19:31 eric 1 0 00087/00000/00000
date and time created 80/06/10 00:19:31 by eric
7.2. Finding why lines were inserted
To find out why you inserted lines, you can get a copy
of the file with each line preceded by the SID that created
sccs get -m prog.c
You can then find out what this delta did by printing the
comments using prt.
To find out what lines are associated with a particular
delta (e.g., 1.3), use:
sccs get -m -p prog.c | grep ´^1.3´
The -p flag causes SCCS to output the generated source to
the standard output rather than to a file.
7.3. Finding what changes you have made
When you are editing a file, you can find out what
changes you have made using:
sccs diffs prog.c
Most of the ``diff'' flags can be used. To pass the -c
flag, use -C.
To compare two versions that are in deltas, use:
sccs sccsdiff -r1.3 -r1.6 prog.c
to see the differences between delta 1.3 and delta 1.6.
8. Shorthand Notations
There are several sequences of commands that get exe
cuted frequently. Sccs tries to make it easy to do these.
A frequent requirement is to make a delta of some file
and then get that file. This can be done by using:
sccs delget prog.c
An Introduction to the Source Code Control System PSD:14-11
which is entirely equivalent to using:
sccs delta prog.c
sccs get prog.c
The "deledit" command is equivalent to "delget" except that
the "edit" command is used instead of the "get" command.
Frequently, there are small bugs in deltas, e.g., com
pilation errors, for which there is no reason to maintain an
audit trail. To replace a delta, use:
sccs fix -r1.4 prog.c
This will get a copy of delta 1.4 of prog.c for you to edit
and then delete delta 1.4 from the SCCS file. When you do a
delta of prog.c, it will be delta 1.4 again. The -r flag
must be specified, and the delta that is specified must be a
leaf delta, i.e., no other deltas may have been made subse
quent to the creation of that delta.
If you found you edited a file that you did not want to
edit, you can back out by using:
sccs unedit prog.c
8.4. The -d flag
If you are working on a project where the SCCS code is
in a directory somewhere, you may be able to simplify things
by using a shell alias. For example, the alias:
alias syssccs sccs -d/usr/src
will allow you to issue commands such as:
syssccs edit cmd/who.c
which will look for the file "/usr/src/cmd/SCCS/who.c". The
file "who.c" will always be created in your current direc
tory regardless of the value of the -d flag.
9. Using SCCS on a Project
Working on a project with several people has its own
set of special problems. The main problem occurs when two
people modify a file at the same time. SCCS prevents this
by locking an s-file while it is being edited.
PSD:14-12 An Introduction to the Source Code Control System
As a result, files should not be reserved for editing
unless they are actually being edited at the time, since
this will prevent other people on the project from making
necessary changes. For example, a good scenario for working
sccs edit a.c g.c t.c
vi a.c g.c t.c
# do testing of the (experimental) version
sccs delget a.c g.c t.c
# should respond "Nothing being edited"
As a general rule, all source files should be deltaed
before installing the program for general use. This will
insure that it is possible to restore any version in use at
10. Saving Yourself
10.1. Recovering a munged edit file
Sometimes you may find that you have destroyed or
trashed a file that you were trying to edit6. Unfortu
nately, you can't just remove it and re-edit it; SCCS keeps
track of the fact that someone is trying to edit it, so it
won't let you do it again. Neither can you just get it
using get, since that would expand the Id keywords.
Instead, you can say:
sccs get -k prog.c
This will not expand the Id keywords, so it is safe to do a
delta with it.
Alternately, you can unedit and edit the file.
10.2. Restoring the s-file
In particularly bad circumstances, the SCCS file itself
may get munged. The most common way this happens is that it
gets edited. Since SCCS keeps a checksum, you will get
errors every time you read the file. To fix this checksum,
sccs admin -z prog.c
6Or given up and decided to start over.
An Introduction to the Source Code Control System PSD:14-13
11. Using the Admin Command
There are a number of parameters that can be set using
the admin command. The most interesting of these are flags.
Flags can be added by using the -f flag. For example:
sccs admin -fd1 prog.c
sets the "d" flag to the value "1". This flag can be
deleted by using:
sccs admin -dd prog.c
The most useful flags are:
b Allow branches to be made using the -b flag to edit.
dSID Default SID to be used on a get or edit. If this is
just a release number it constrains the version to a
particular release only.
i Give a fatal error if there are no Id Keywords in a
file. This is useful to guarantee that a version of
the file does not get merged into the s-file that has
the Id Keywords inserted as constants instead of
y The "type" of the module. Actually, the value of
this flag is unused by SCCS except that it replaces
the %Y% keyword.
The -tfile flag can be used to store descriptive text
from file. This descriptive text might be the documentation
or a design and implementation document. Using the -t flag
insures that if the SCCS file is sent, the documentation
will be sent also. If file is omitted, the descriptive text
is deleted. To see the descriptive text, use "prt -t".
The admin command can be used safely any number of
times on files. A file need not be gotten for admin to
12. Maintaining Different Versions (Branches)
Sometimes it is convenient to maintain an experimental
version of a program for an extended period while normal
maintenance continues on the version in production. This
can be done using a "branch." Normally deltas continue in a
straight line, each depending on the delta before. Creating
a branch "forks off" a version of the program.
The ability to create branches must be enabled in
PSD:14-14 An Introduction to the Source Code Control System
sccs admin -fb prog.c
The -fb flag can be specified when the SCCS file is first
12.1. Creating a branch
To create a branch, use:
sccs edit -b prog.c
This will create a branch with (for example) SID 18.104.22.168.
The deltas for this version will be numbered 1.5.1.n.
12.2. Getting from a branch
Deltas in a branch are normally not included when you
do a get. To get these versions, you will have to say:
sccs get -r1.5.1 prog.c
12.3. Merging a branch back into the main trunk
At some point you will have finished the experiment,
and if it was successful you will want to incorporate it
into the release version. But in the meantime someone may
have created a delta 1.6 that you don't want to lose. The
sccs edit -i22.214.171.124-1.5.1 prog.c
sccs delta prog.c
will merge all of your changes into the release system. If
some of the changes conflict, get will print an error; the
generated result should be carefully examined before the
delta is made.
12.4. A more detailed example
The following technique might be used to maintain a
different version of a program. First, create a directory
to contain the new version:
Edit a copy of the program on a branch:
sccs -d../xyz edit prog.c
When using the old version, be sure to use the -b flag to
info, check, tell, and clean to avoid confusion. For
An Introduction to the Source Code Control System PSD:14-15
sccs info -b
when in the directory "xyz".
If you want to save a copy of the program (still on the
branch) back in the s-file, you can use:
sccs -d../xyz deledit prog.c
which will do a delta on the branch and reedit it for you.
When the experiment is complete, merge it back into the
s-file using delta:
sccs -d../xyz delta prog.c
At this point you must decide whether this version should be
merged back into the trunk (i.e. the default version),
which may have undergone changes. If so, it can be merged
using the -i flag to edit as described above.
12.5. A warning
Branches should be kept to a minimum. After the first
branch from the trunk, SID's are assigned rather haphaz
ardly, and the structure gets complex fast.
13. Using SCCS with Make
SCCS and make can be made to work together with a lit
tle care. A few sample makefiles for common applications
There are a few basic entries that every makefile ought
to have. These are:
a.out (or whatever the makefile generates.) This entry
regenerates whatever this makefile is supposed to
regenerate. If the makefile regenerates many
things, this should be called "all" and should in
turn have dependencies on everything the makefile
install Moves the objects to the final resting place,
doing any special chmod's or ranlib's as appropri
sources Creates all the source files from SCCS files.
clean Removes all files from the current directory that
can be regenerated from SCCS files.
PSD:14-16 An Introduction to the Source Code Control System
print Prints the contents of the directory.
The examples shown below are only partial examples, and may
omit some of these entries when they are deemed to be obvi
The clean entry should not remove files that can be
regenerated from the SCCS files. It is sufficiently impor
tant to have the source files around at all times that the
only time they should be removed is when the directory is
being mothballed. To do this, the command:
can be used. This will remove all files for which an s-file
exists, but which is not being edited.
13.1. To maintain single programs
Frequently there are directories with several largely
unrelated programs (such as simple commands). These can be
put into a single makefile:
LDFLAGS= -i -s
$(CC) $(LDFLAGS) -o prog prog.o
prog.o: prog.c prog.h
$(CC) $(LDFLAGS) -o example example.o
sccs get $<
The trick here is that the .DEFAULT rule is called every
time something is needed that does not exist, and no other
rule exists to make it. The explicit dependency of the .o
file on the .c file is important. Another way of doing the
same thing is:
An Introduction to the Source Code Control System PSD:14-17
SRCS= prog.c prog.h example.c
LDFLAGS= -i -s
$(CC) $(LDFLAGS) -o prog prog.o
$(CC) $(LDFLAGS) -o example example.o
sccs get $@
There are a couple of advantages to this approach: (1) the
explicit dependencies of the .o on the .c files are not
needed, (2) there is an entry called "sources" so if you
want to get all the sources you can just say "make sources",
and (3) the makefile is less likely to do confusing things
since it won't try to get things that do not exist.
13.2. To maintain a library
Libraries that are largely static are best updated
using explicit commands, since make doesn't know about
updating them properly. However, libraries that are in the
process of being developed can be handled quite adequately.
The problem is that the .o files have to be kept out of the
library as well as in the library.
PSD:14-18 An Introduction to the Source Code Control System
# configuration information
OBJS= a.o b.o c.o d.o
SRCS= a.c b.c c.c d.s x.h y.h z.h
GET= sccs get
$(AR) rvu lib.a $(OBJS)
cp lib.a $(TARG)/lib.a
$(GET) $(REL) $@
pr *.h *.[cs]
rm -f *.o
rm -f core a.out $(LIB)
The "$(REL)" in the get can be used to get old versions
easily; for example:
make b.o REL=-r1.3
The install entry includes the line "sccs check" before
anything else. This guarantees that all the s-files are up
to date (i.e., nothing is being edited), and will abort the
make if this condition is not met.
13.3. To maintain a large program
An Introduction to the Source Code Control System PSD:14-19
OBJS= a.o b.o c.o d.o
SRCS= a.c b.c c.y d.s x.h y.h z.h
GET= sccs get
$(CC) $(LDFLAGS) $(OBJS) $(LIBS)
$(GET) $(REL) $@
(The print and clean entries are identical to the previous
case.) This makefile requires copies of the source and
object files to be kept during development. It is probably
also wise to include lines of the form:
a.o: x.h y.h
c.o: x.h y.h z.h
so that modules will be recompiled if header files change.
Since make does not do transitive closure on dependen
cies, you may find in some makefiles lines like:
This would be used in cases where file z.h has a line:
in order to bring the mod date of z.h in line with the mod
date of x.h. When you have a makefile such as above, the
touch command can be removed completely; the equivalent
effect will be achieved by doing an automatic get on z.h.
14. Further Information
The SCCS/PWB User's Manual gives a deeper description
of how to use SCCS. Of particular interest are the number
ing of branches, the l-file, which gives a description of
what deltas were used on a get, and certain other SCCS com
The SCCS manual pages are a good last resort. These
should be read by software managers and by people who want
to know everything about everything.
PSD:14-20 An Introduction to the Source Code Control System
Both of these documents were written without the sccs
front end in mind, so most of the examples are slightly dif
ferent from those in this document.
An Introduction to the Source Code Control System PSD:14-21
The following commands should all be preceded with
"sccs". This list is not exhaustive; for more options see
get Gets files for compilation (not for editing). Id
keywords are expanded.
-rSID Version to get.
-p Send to standard output rather than to the
-k Don't expand id keywords.
-ilist List of deltas to include.
-xlist List of deltas to exclude.
-m Precede each line with SID of creating
-cdate Don't apply any deltas created after date.
edit Gets files for editing. Id keywords are not
expanded. Should be matched with a delta command.
-rSID Same as get. If SID specifies a release
that does not yet exist, the highest num
bered delta is retrieved and the new delta
is numbered with SID.
-b Create a branch.
-ilist Same as get.
-xlist Same as get.
delta Merge a file gotten using edit back into the s-
file. Collect comments about why this delta was
unedit Remove a file that has been edited previously with
out merging the changes into the s-file.
prt Produce a report of changes.
PSD:14-22 An Introduction to the Source Code Control System
-t Print the descriptive text.
-e Print (nearly) everything.
info Give a list of all files being edited.
-b Ignore branches.
Ignore files not being edited by user.
check Same as info, except that nothing is printed if
nothing is being edited and exit status is
tell Same as info, except that one line is produced per
file being edited containing only the file name.
clean Remove all files that can be regenerated from the
what Find and print id keywords.
admin Create or set parameters on s-files.
-ifile Create, using file as the initial contents.
-z Rebuild the checksum in case the file has
-fflag Turn on the flag.
-dflag Turn off (delete) the flag.
-tfile Replace the descriptive text in the s-file
with the contents of file. If file is
omitted, the text is deleted. Useful for
storing documentation or "design & imple
mentation" documents to insure they get
distributed with the s-file.
Useful flags are:
b Allow branches to be made using the -b flag
dSID Default SID to be used on a get or edit.
i Cause "No Id Keywords" error message to be
a fatal error rather than a warning.
t The module "type"; the value of this flag
replaces the %Y% keyword.
An Introduction to the Source Code Control System PSD:14-23
fix Remove a delta and reedit it.
delget Do a delta followed by a get.
deledit Do a delta followed by an edit.
2. Id Keywords
%Z% Expands to "@(#)" for the what command to find.
%M% The current module name, e.g., "prog.c".
%I% The highest SID applied.
%W% A shorthand for "%Z%%M% <tab> %I%".
%G% The date of the delta corresponding to the "%I%" key
%R% The current release number, i.e., the first component
of the "%I%" keyword.
%Y% Replaced by the value of the t flag (set by admin).
Man(1) output converted with