src(1) Manual Page

src [command] [revision-spec] ['file'…​]

SRC (or src) is simple revision control, a version-control system for single-file projects by solo developers and authors. It modernizes the venerable RCS, hence the anagrammatic acronym. The design is tuned for use cases like all those little scripts in your ~/bin directory, or a directory full of single-file HOWTOs.

SRC revision histories are single, human-readable files beneath a hidden .src subdirectory in the directory where they live. There may be multiple histories under one directory; SRC treats them as separate projects, and history files can be moved elsewhere at any time.

SRC gives you simple, consecutive integer revision numbers. It supports tags and branching. It records commit timestamps, but does not show committer information, because the committer is always you. The command set is intended to look familiar if you have ever used Subversion, Mercurial, or Git.

SRC is lightweight and fast. It uses two small self-contained executables, with no libraries and no complications.

SRC interprets the EDITOR variable in the usual way, using it to spawn an editor instance when you perform a commit or amend. If EDITOR is not set it has a fallback list of editors it looks for, beginning with various ways to invoke Emacs and vi.

SRC is fully supported in Emacs VC mode.

A "revision" is a 1-origin integer, or a tag name designating an integer revision, or a branch name designating the tip revision of its branch. Revision numbers always increase in commit-date order.

A revision range is a single revision, or a pair of revisions "M-N" (all revisions numerically from M to N) or "M..N" (all revisions that are branch ancestors of N and branch successors of M).

If SRC complains that your revision spec looks like a nonexistent filename, you can prefix it with "@" (this is always allowed). "@" by itself means the current (checked-out) revision.

A filename can be a path. In that case SRC will behave as though it were running in the lowest-level directory on the path and called with the path basename.

Unless otherwise noted under individual commands, the default revision is the tip revision on the current branch and the default range is all revisions on the current branch.

The token "--" tells the command-line interpreter that subcommands, switches, and revision-specs are done - everything after it is a filename, even if it looks like a subcommand or revision number.

The omission of "src remove" is a deliberate speed bump.

If no files are specified, all eligible files are operated on in sequence.

Silence is golden. When you have selected only one file to operate on, and the command is not a report generator ('status', 'cat', 'log', 'list', 'fast-export', the listing modes of 'tag' and 'branch', 'ls') you will see a reply only if the operation failed.

Other commands ('commit', 'checkout', tag creation and deletion) give you a success message per file when operating on multiple files, so you will not be in doubt about which operation succeeded. This behavior can be suppressed with the '-q' option, placed 'before' the subcommand word.

If your directory contains a file named ".srcignore", each line that is neither blank nor begins with a "#" is interpreted as an ignore pattern. It is expanded with glob(3), and files in the expansion are omitted from 'src status' - unless the file is named as an argument, of the status command, in which case its status is "I". Thus, for example, a line reading "*.html" will cause all files with an HTML extension to be omitted from the output of "src status", but the output of 'src status *' will list them with status "I".

SRC history files are (normally) RCS master files. SRC maintains no permanent state other than these files.

In order to maintain complete backwards compatibility, one other compromise was made: any commit comment containing a string exactly matching an RCS log delimiter (a long string of "-" characters) will be rejected as malformed.

The RCS back end will be automatically selected when there is an .src or RCS subdirectory. If both these directories exist, SRC will operate on .src and preserve the RCS directory; in this case it will be a little extra verbose to leave no doubt about what it is doing.

You can explicitly select the RCS back end by making the first command keyword on the src command line be 'rcs'. This should only be necessary when your working directory contains two or more of the subdirectories .src, RCS, and SCCS.

If your directory has both a .src and an unrelated RCS directory you can force SRC to work on the RCS directory and ignore .src by giving it the option "-S RCS".

By default, history files are kept in a hidden subdirectory named .src. But if you have an RCS subdirectory and no .src, SRC will quietly operate on the files in the RCS directory in a completely backward-compatible way.

Using SCCS as a back end is also supported, with some limits due to missing features in SCCS implementations:

The SCCS back end will be automatically selected when there is an SCCS subdirectory and no .src or RCS subdirectory.

You can explicitly select the SCCS back end by making the first command keyword on the src command line be 'sccs'. This should only be necessary when your working directory contains none or two or more of the subdirectories .src, RCS, and SCCS.

Working with SCCS requires an SCCS subdirectory; SRC will quietly create one, if required, then operate on the files in the SCCS directory in a completely backward-compatible way.

Fast-import to SCCS is not supported.

The SCCS mode is not recommended unless you have a specific need to work with legacy SCCS repositories. Up-converting them to something less Paleolithic (e.g. with sccs2rcs(1) or reposurgeon(1)) would be a better idea; in truth, the SCCS support exists mainly because it’s hilarious (for obscure hacker values of 'hilarious').

These will be of interest mainly to developers. They must go before the subcommand.

A '-d' (debug) option before the main command word turns on debugging messages. Just one "-d" gives you complete visibility about what commands the back end is running and what (if any) diagnostic output they ship. It can be repeated for higher debugging levels that expose more of src’s internal computation.

A '-L' option sets a log file to which debug output should be written Without this option it is written to standard error.

A '-S' (sandbox) option can be used to set the repository directory to something other than its default of .src. Use "-S RCS" to make src operate on an RCS directory even if there is already a .src directory.

A '-T' option sets up an artificial clock that ticks once on each revision and fixes the user information to be used in 'fast-export'; It also attributes all commits to "J. Random Hacker". It is for regression testing.

SRC is written in Python and requires 2.7 or later; it will run under Python 3.x for x > 2.

If you wish to use the RCS support (recommended), the RCS tools at version 5.7 or later must be installed and accessible in your $PATH.

If you wish to use the SCCS support, some implementation of SCCS must be accessible. GNU’s CSSC (Compatibly Stupid Source Control) will work; so will the SunOS and Schilling forks of AT&T SCCS.

The rcs-fast-import(1) tool at version 1.3 or later is required to support the 'src fast-import' command.

SRC will die gracefully with a useful error message when it fails due to a missing back end.

SRC will unconditionally bail out if a directory named RCS-save exists. This is because in order to be able to use .src when an unrelated RCS subdirectory is also present, SRC has to play a game of three-directory monte. Before doing its work it moves RCS to RCS-save, then moves .src to RCS; after doing its work it moves RCS to .src and RCS-save to RCS. If there is a pre-existing RCS-save this maneuver can’t be done. If you trip over such a pre-exiting RCS-save, this probably means SRC previously underwent a hard crash and you will have to reshuffle these directories by hand. No bug that can produce such a crash has yet been reported.

The directory shuffle also means that running more than one SRC edit session on the same directory at the same time may produce mysterious failures. Don’t do this - it is way outside the tool’s intended performance envelope.

Branch deletions change the revision numbers of revisions downstream of the branch join.

In src fast-export dumps of repositories with tags, branch labels may not exactly match what git fast-export would emit.

In both RCS and SCCS revision numbers normally looked like "1.n" for n starting at 1 and monotonically increasing. It was possible to check in a change with a higher release number (for example, "2.1"), though this was seldom done. If you use SRC to view or edit an ancient master that used this feature, commands using ranges and named branches will not always work as expected.

Report bugs to Eric S. Raymond <esr@thyrsus.com>. The project page is at http://catb.org/~esr/src

rcs(1), rcs-fast-import(1), sccs(1), svn(1), hg(1), git(1), dot(1), sccs2rcs.