The get(CP) command creates a file containing a specified version of an SCCS file. The version is retrieved by beginning with the initial version and then applying deltas, in order, until the desired version is obtained. The resulting file is called the `g-file'. It is created in the current directory and owned by the real user. The mode assigned to the g-file depends on how the get command is used.
The most common use of get is:
This retrieves the latest version of file abc from the SCCS file tree trunk and produces (for example) on the standard output:
1.3 67 lines No id keywords (cm7)This means version 1.3 of file s.abc has been retrieved (assuming 1.3 is the latest trunk delta), it has 67 lines of text, and no ID keywords have been substituted in the file.
The generated g-file (file abc) is given access permission mode 444 (read only). This particular way of using get produces g-files only for inspection, compilation, and so on. It is not intended for editing (making deltas).
When several files are specified, the same information is output for each one.
For example, enter:
get s.abc s.xyz
s.abc: 1.3 67 lines No id keywords (cm7)
s.xyz: 1.7 85 lines No id keywords (cm7)
In generating a g-file for compilation, it is useful
to record the date and time of creation, the version retrieved,
and the module's name within the g-file.
This information can eventually appear in a load module when one is created.
SCCS provides a convenient mechanism for doing this automatically.
Identification (ID) keywords appearing anywhere in the generated file
are replaced by appropriate values according to the definitions
of those ID keywords.
The format of an ID keyword is an uppercase letter
enclosed by percent signs (%).
In this example, I is the ID keyword replaced by the SID of the retrieved version of a file. Similarly, %H% is the current date in MM/DD/YY format and %M% is the name of the g-file. When get is executed on an SCCS file containing the following PL/1 declaration:
DCL ID CHAR(100) VAR INIT('%M% %I% %H%');The PL/1 declaration produces the following:
DCL ID CHAR(100) VAR INIT('MODNAME 2.3 07/18/85');For a complete list of the approximately 20 ID keywords provided, see get(CP).
When no ID keywords are substituted by get, the following message is issued:
No id keywords (cm7)This message is normally treated as a warning by get, although the presence of the SCCS file i flag causes it to be treated as an error. For a complete list of the SCCS file flags, see admin(CP).
The version of an SCCS file that get retrieves is the most recently created delta of the highest-numbered trunk release. However, any other version can be retrieved with get -r by specifying the version's SID. The following command retrieves version 1.3 of file s.abc and produces the sample message on the standard output:
get -r1.3 s.abc 1.3 64 linesA branch delta can be retrieved similarly, as demonstrated with the following command and sample output:
get -r184.108.40.206 s.abc 220.127.116.11 234 linesWhen an SID is specified and the particular version does not exist in the SCCS file, an error message results.
The level number can be omitted, causing the retrieval of the trunk delta with the highest level number within the given release. The following command and sample output illustrate:
get -r3 s.abc 3.7 213 linesIf the specified release does not exist, get retrieves the trunk delta with the highest level number within the highest-numbered existing release that is lower than the given release. In the following example, release 9 is specified for retrieval. However, since the specified release does not exist, trunk delta 7.6 is retrieved as the latest version of file s.abc below release 9.
get -r9 s.abc 7.6 420 linesFor details on numbering by delta's see ``Delta numbering''.
Similarly, omitting the sequence number, for example, results in the retrieval of the branch delta with the highest sequence number on the given branch. (If the given branch does not exist, an error message results.)
get -r4.3.2 s.abc 18.104.22.168 89 linesThe get -t command retrieves the latest (top) version of a particular release when no -r is used or when its value is simply a release number. The latest version is the delta produced most recently, independent of its location on the SCCS file tree. The following command (and sample output) illustrate this for a case where the most recent delta in release 3 is 3.5:
get -r3 -t s.abc 3.5 59 linesHowever, if branch delta 22.214.171.124 were the latest delta (created after delta 3.5), the same command might produce:
126.96.36.199 46 lines
The get -e command indicates an intent to make a delta. First, get checks the following conditions:
floor is less than or equal to R, which is less than or equal to ceiling.This check determines whether the release being accessed is protected. The floor and ceiling are SCCS file flags, representing start and end of range.
A failure of any of the first three conditions causes the processing of the corresponding SCCS file to terminate.
If the above checks succeed, get -e causes the creation of a g-file in the current directory with mode 644 (readable by everyone, writable only by the owner) owned by the real user. If a writable g-file already exists, get terminates with an error. This is to prevent inadvertent destruction of a g-file while it is being edited for the purpose of making a delta. Any ID keywords appearing in the g-file are not substituted by get -e because the generated g-file is subsequently used to create another delta. Replacement of ID keywords causes them to be permanently changed in the SCCS file. As a direct result of this, get does not check for presence of ID keywords in the g-file. The following message is never output when get -e is used.
No id keywords (cm7)In addition, get -e causes the creation (or updating) of a p-file that is used to pass information to the delta command.
get -e s.abc
The output of this command is:
1.3 new delta 1.4 67 lines
There may be times when a file is erroneously retrieved for editing,
such as when there is really no editing that needs to be done at the time.
In such cases, the
command cancels the
delta reservation that was set up.
For example, enter either of the following commands:
unget -r1.4 s.abc
These commands produce:
If get -r and/or -t keys are used together with the -e option, the version retrieved for editing is specified with -r and/or -t.
The get -i and -x commands specify a list of deltas to be included and excluded, respectively. (See get(CP) for the syntax of such a list.) Including a delta means forcing its changes to be included in the retrieved version. This is useful in applying the same changes to more than one version of the SCCS file. Excluding a delta means forcing it not to be applied. This may be used to undo the effects of a previous delta in the version to be created.
Whenever deltas are included or excluded, get checks for possible interference with other deltas. For example, two deltas can interfere when each one changes the same line of the retrieved g-file. A warning shows the range of lines within the retrieved g-file where the problem may exist.
The get -i and get -x commands should be used with care.
The get -k command has two uses.
The first is to regenerate a g-file
that may have been accidentally removed or corrupted after get -e.
The second use is to generate a g-file in which the replacement of ID keywords
has been suppressed.
A g-file generated by get -k is identical to one produced by
the get -e command.
However, no processing related to the p-file takes place.
The ability to retrieve different versions of an SCCS file allows
several deltas to be in progress at any given time.
This means that several get -e commands
may be executed on the same file unless two
executions retrieve the same version
or multiple concurrent edits are allowed.
The p-file created by get -e is named by automatic replacement of the SCCS filename's prefix s. with p.. It is created in the same directory as the SCCS file, given mode 644 (readable by everyone, writable only by the owner), and owned by the effective user. The p-file contains the following information for each delta that is still in progress:
It should be noted that concurrent executions of get must be carried out from different directories. Subsequent executions from the same directory attempt to overwrite the g-file, which is an SCCS error condition. In practice, this problem does not arise because each user normally has a different working directory.
For a discussion of how different users
are permitted to use SCCS commands on the same files, see
``Determination of new SID'' shows the possible SID components a user can specify with get (left-most column), the version that is then retrieved by get, and the resulting SID for the delta, which delta creates (right-most column).
Determination of new SID
|SID||b key-||Other||SID||SID of delta|
|specified||letter||conditions||retrieved||to be created|
|in get||used+||by get||by delta|
|none++||no||R defaults to mR||mR.mL||mR.(mL+1)|
|none++||yes||R defaults to mR||mR.mL||mR.mL.(mB+1).1|
|R||no||R > mR||mR.mL||R.1§|
|R||no||R = mR||mR.mL||mR.(mL+1)|
|R||yes||R > mR||mR.mL||mR.mL.(mB+1).1|
|R||yes||R = mR||mR.mL||mR.mL.(mB+1).1|
|R||R< mR and R||hR.mL||hR.mL.(mB+1).1|
|does not exist|
|release > R,|
|and R exists|
|in release R|
|Footnotes , +, ++, §, and on next page.|
Under normal conditions, more than one get -e for the same SID is not permitted. That is, delta must be executed before a subsequent get -e is executed on the same SID.
Multiple concurrent edits are allowed if the
SCCS file j flag is set.
get -e s.abc
1.1 new delta 1.2 5 linesThis can be immediately followed by (without an intervening delta):
1.1 new delta 188.8.131.52 5 linesIn this case, a delta after the first get produces delta 1.2 (assuming that 1.1 is the most recent trunk delta), and a delta after the second get produces delta 184.108.40.206.
The get -p command causes the retrieved text to be written
to the standard output, rather than to a g-file.
In addition, all output normally directed to the standard output
(such as the SID of the version retrieved and the number of lines
is directed instead to the diagnostic output.
The get -p command creates a g-file
with an arbitrary name, as in:
get -p s.abc > arbitrary-filename
The get -s command suppresses output normally directed to the
standard output, such as the SID of the retrieved version and the
number of lines retrieved, but it does not
affect messages normally directed to the diagnostic output.
The get -s command prevents nondiagnostic messages
from appearing on the user's terminal and is often used with -p
to pipe the output, as in:
get -p -s s.abc | pg
The get -g command suppresses the
retrieval of the text of an SCCS file.
This is useful in several ways.
It may be used to verify a particular SID in an SCCS file. For example:
get -g -r4.3 s.abc
This outputs the SID 4.3 if it exists in the SCCS file s.abc, or an error message if it does not.
Another use of get -g is in regenerating a p-file
that may have been accidentally destroyed, as in:
get -e -g s.abc
The get -l command causes SCCS to create an `l-file'. It is named by replacing the s. of the SCCS filename with l., created in the current directory with mode 444 (read only) and owned by the real user. The l-file contains a table showing the deltas used in constructing a particular version of the SCCS file. See get(CP) for a description of the delta table format.
The following command generates an l-file, showing the deltas
applied to retrieve version 2.3 of file s.abc.
get -r2.3 -l s.abc
Specifying p with -l, for example, results in the output
being written to the standard output, rather than to the l-file.
get -lp -r2.3 s.abc
The get -g command can be used with -l
to suppress the retrieval of the text.
get -g -l s.abc
The get -m command identifies the changes applied to an SCCS file. Each line of the g-file is preceded by the SID of the delta that caused the line to be inserted. The SID is separated from the text of the line by a tab character.
The get -n command causes each line of a g-file
to be preceded by the value of the ID keyword and a tab character.
This is most often used in a pipeline with
For example, to find
all lines that match a given pattern in the latest version of each
SCCS file in a directory, the following can be executed:
get -p -n -s directory | grep pattern
If both -m and -n are specified, each line of the generated g-file is preceded by the value of the %M% ID keyword and a tab (the effect of -n), and is followed by the line in the format produced by -m. Because use of -m and/or -n causes the contents of the g-file to be modified, such a g-file must not be used for creating a delta. Therefore, neither -m nor -n may be specified together with get -e.