checkout − RCS check-out utility


checkout [options] [file-specifications]


Checkout is an extension of the RCS utility co. It uses a file’s check-in date to set the file’s modification date after check-out.


Checkout uses the rcs utility co. It is normally invoked from the rcsget script, but may be invoked in a standalone manner. Checkout differs from co primarily in its treatment to the delta date: after invoking co, checkout sets the file’s modification date to match the delta-date for the extracted version.

Set-UID Operation
Like the checkin utility, checkout properly handles set-uid operation for a non-root effective user. The archived files are owned by the effective user, and the checked-out files are owned by the real user.

Note that since checkin initializes the access list in the archive files, the real user must appear on the access list to lock a file. Of course, if no lock is made, then the user need not be on the access list.


Checkout recognizes all of the "co" options except for the "−d" cutoff date. Instead, the "−c" option is used:

specifies the rcs cutoff date, in SCCS-format


Punctuation in the date is permitted. For example,

-c 77/2/2 9:22:25
-c 770202092225

represent the same date. This option is translated to the co "−d" option.

Use the "−x" option of checkout to direct it to retain the pathname when translating between working and archive files, e.g, "path/name" becomes "path/RCS/name,v". If the "−x" option is not set, "path/name" becomes "./RCS/name,v", and "path/RCS/name,v" becomes "./name".


To extract files using checkout, you must provide one or more file names. For each name, checkout parses the leaf-name and extracts the specified version from the "./RCS" directory.


Checkout is a C-language program. It invokes co via an execlp call (so that co must be in your path), and performs pre- and postprocessing of the archive and working file to determine the delta-date to use for the extracted file. Environment variables used by checkout include:

if defined, specifies the directory in which rcs
archive files are found. Normally files are found in "./RCS".


is the POSIX time zone, which is overridden internally so that file modification dates are independent of the local time zone.


Checkout uses the following files:


the RCS check-out program


This does not handle rcs branches properly.

Checkout does not handle the "−j" and "−p" options of co.


checkin, rcsput, ded, ci (1), co (1)


Thomas E. Dickey <>