diffutils: Revision Control
10.2 Revision Control
=====================
If a nonexistent input file is under a revision control system supported
by 'patch', 'patch' normally asks the user whether to get (or check out)
the file from the revision control system. Patch currently supports
RCS, ClearCase and SCCS. Under RCS and SCCS, 'patch' also asks when the
input file is read-only and matches the default version in the revision
control system.
The '--get=NUM' ('-g NUM') option affects access to files under
supported revision control systems. If NUM is positive, 'patch' gets
the file without asking the user; if zero, 'patch' neither asks the user
nor gets the file; and if negative, 'patch' asks the user before getting
the file. The default value of NUM is given by the value of the
'PATCH_GET' environment variable if it is set; if not, the default value
is zero if 'patch' is conforming to POSIX, negative otherwise. ⇒
patch and POSIX.
The choice of revision control system is unaffected by the
'VERSION_CONTROL' environment variable (⇒Backup Names).