co(1) co(1)NAME co - checks out RCS revisions SYNOPSIS co [-ddate] [-jjoinlist] [-l[rev]] [-p[rev]] [-q[rev]] [-r[rev]] [-sstate] [-w[login]] files ARGUMENTS -ddate Retrieves the latest revision on the selected branch whose checkin date/time is less than or equal to date. The date and time may be given in free format and are converted to local time. Examples of acceptable formats for date are: 22-April-1985, 17:20-CDT 2:25 AM, Dec. 29, 1987 Tue-PDT, 1986, 4pm Jul 21 Fri Apr 16 15:52:25 EST 1988 The last example illustrates the format produced by ctime(3) and date(1). Most fields in the date and time may be defaulted. co determines the defaults in this order: year, month, day, hour, minute, and second (that is, from most to least significant). At least one of these fields must be provided. For omitted fields that are of higher significance than the highest provided field, the current values are assumed. For all other omitted fields, the lowest possible values are assumed. For example, the date 20, 10:30 defaults to 10:30:00 of the 20th of the current month and current year. The date specified on the command line must be in quotation marks if it contains spaces. files Specifies the RCS files to be checked out. -jjoinlist Generates a new revision that is the join of the revisions on joinlist. The joinlist is a comma- separated list of pairs of the form rev2:rev3, where rev2 and rev3 are (symbolic or numeric) revision numbers. For the initial pair, rev1 denotes the revision selected by the options -l,...,-w. For all other pairs, rev1 denotes the revision generated by the previous pair. (Thus, the output of one join becomes the input to the next.) For each pair, co joins revisions rev1 and rev3 with respect to rev2. This means that all changes that transform rev2 into rev1 are applied to a copy of rev3. This is particularly useful if rev1 and rev3 are the January 1992 1
co(1) co(1)ends of two branches that have rev2 as a common ancestor. If rev1 < rev2 < rev3 are on the same branch, joining generates a new revision, which is like rev3, but with all changes that lead from rev1 to rev2 undone. If changes from rev2 to rev1 overlap with changes from rev2 to rev3, co prints a warning and includes the overlapping sections, delimited by the lines <<<<<<< rev1, =======, and >>>>>>> rev3. For the initial pair, rev2 may be omitted. The default is the common ancestor. If any of the arguments indicate branches, the latest revisions on those branches are assumed. If the -l option is present, the initial rev1 is locked. -l[rev] Locks the checked-out revision for the caller. If omitted, the checked-out revision is not locked. See the -r option for handling of the revision number rev. -p[rev] Prints the retrieved revision on the standard output rather than storing it in the working file. This option is useful when co is part of a pipe. -q[rev] Specifies quiet mode; error messages are not printed. -r[rev] Retrieves the latest revision whose number is less than or equal to rev. If rev indicates a branch rather than a revision, the latest revision on that branch is retrieved. rev is composed of one or more numeric or symbolic fields separated by a period, (.). The numeric equivalent of a symbolic field is specified with the -n option of the commands ci and rcs. -sstate Retrieves the latest revision on the selected branch whose state is set to state. -w[login] Retrieves the latest revision on the selected branch that was checked in by the user with login name login. If the argument login is omitted, the caller's login name is assumed. DESCRIPTION co retrieves revisions from RCS files. Each filename ending in ,v is taken to be an RCS file. All other files are assumed to be working files. co retrieves a revision from each RCS file and stores it in the corresponding working 2 January 1992
co(1) co(1)file. Pairs of RCS files and working files may be specified in three ways (see the EXAMPLES section later in this entry). (1) Both the RCS file and the working file are given. The RCS filename is of the form path1/workfile,v and the working filename is of the form path2/workfile, where path1 and path2 are (possibly different or empty) paths and workfile is a filename. (2) Only the RCS file is given. Then the working file is created in the current directory and its name is derived from the name of the RCS file by removing path1/ and the suffix ,v. (3) Only the working file is given. Then the name of the RCS file is derived from the name of the working file by removing path2/ and appending the suffix ,v. If the RCS file is omitted or specified without a path, then co looks for the RCS file, first in the directory ./RCS and then in the current directory. Revisions of an RCS file may be checked-out locked or unlocked. Locking a revision prevents overlapping updates. A revision checked out for reading or processing (for example, compiling) need not be locked. A revision checked out for editing and later check-in must normally be locked. Locking a revision currently locked by another user fails. (A lock may be broken with the rcs(1) command.) co with locking requires the caller to be on the access list of the RCS file, unless he is the owner of the file or the superuser, or the access list is empty. co without locking is not subject to access-list restrictions. A revision is selected by number, check-in date/time, author, or state. If none of these options is specified, the latest revision on the trunk is retrieved. When the options are applied in combination, the latest revision that satisfies all of them is retrieved. The options for date/time, author, and state retrieve a revision on the selected branch. The selected branch is either derived from the revision number (if given) or is the highest branch on the trunk. A revision number may be attached to one of the options -l, -p, -q, or -r. A co command applied to an RCS file with no revisions creates a zero-length file. The co command always performs keyword substitution, as follows. January 1992 3
co(1) co(1)The caller of the command must have write permission in the working directory, read permission for the RCS file, and either read permission (for reading) or read/write permission (for locking) in the directory that contains the RCS file. A number of temporary files are created. A semaphore file is created in the directory of the RCS file to prevent simultaneous updates. Keyword Substitution Strings of the form $keyword$ and $keyword:...$ embedded in the text are replaced with strings of the form $keyword: value $, where keyword and value are pairs as listed. Keywords may be embedded in literal strings or comments to identify a revision. Initially, the user enters strings of the form $keyword$. On checkout, co replaces these strings with strings that are of the form $keyword: value $. If a revision containing strings of the latter form is checked back in, the value fields will be replaced during the next checkout. Thus, the keyword values are automatically updated on checkout. Keywords and their corresponding values are as follows: $Author$ The login name of the user who checked in the revision. $Date$ The date and time the revision was checked in. $Header$ A standard header containing the RCS filename, the revision number, the date, the author, and the state. $Locker$ The login name of the user who locked the revision (empty if not locked). $Log$ The log message supplied during checkin, preceded by a header containing the RCS filename, the revision number, the author, and the date. Existing log messages are not replaced. Instead, the new log message is inserted after $Log:... $. This is useful for accumulating a complete change log in a source file. $Revision$ The revision number assigned to the revision. 4 January 1992
co(1) co(1)$Source$ The full pathname of the RCS file. $State$ The state assigned to the revision with rcs -s or ci -s. File Modes The working file inherits the read and execute permissions from the RCS file. In addition, the owner-write permission is turned on unless the file is checked out unlocked and locking is set to strict (see rcs(1)). If a file with the name of the working file already exists and has write permission, co cancels the checkout if the -q option is given, or asks whether to cancel if the -q option is not given. If the existing working file is not writable, it is deleted before the checkout. EXAMPLES Suppose the current directory contains a subdirectory RCS with an RCS file io.c,v. Then all of the following commands retrieve the latest revision from RCS/io.c,v and store it into io.c. co io.c co RCS/io.c,v co io.c,v co io.c RCS/io.c,v co io.c io.c,v co RCS/io.c,v io.c co io.c,v io.c STATUS MESSAGES AND VALUES The RCS filename, the working filename, and the revision number retrieved are written to the diagnostic output. The exit status always refers to the last file checked out, and is 0 if the operation was successful, 1 if otherwise. LIMITATIONS The -d option gets confused in some circumstances and accepts no date before 1970. There is no way to suppress the expansion of keywords, except by writing them differently. In nroff and troff, this is done by embedding the null-character \& into the keyword. The -j option does not work for files that contain lines with a single .. January 1992 5
co(1) co(1)NOTES Author: Walter F. Tichy, Purdue University, West Lafayette, IN 47907.cCopyright 1982 by Walter F. Tichy.FILES /bin/co Executable file SEE ALSO ci(1), ident(1), rcs(1), rcsdiff(1), rcsintro(1), rcsmerge(1), rlog(1) sccstorcs(1M) in A/UX System Administrator's Reference rcsfile(4) in A/UX Programmer's Reference Walter F. Tichy, ``Design, Implementation, and Evaluation of a Revision Control System,'' in Proceedings of the 6th International Conference on Software Engineering, IEEE, Tokyo, Sept. 1982 6 January 1992