src — simple revision control


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 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 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 interprets the EDITOR variable in the usual way, using it to spawn an editor instance when you perform a commit or amend.

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.

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.

src help [command]
Displays help for commands.
src commit [-|-m string|-f file|-e] [file…]
Enters a commit for specified files. Separately to each one. A history is created for the file if it does not already exist. With -, take comment text from stdin; with -m use the following string as the comment; with -f take from a file. With -e, edit even after -, -f or -m. "ci" is a synonym for "commit".
src amend [-|-m string|-f file|-e] [revision] [file…]
Amends the stored comment for a specified revision, defaulting to the latest revision on the current branch. Flags are as for commit. "am" is a synonym for "amend".
src checkout [revision] [file…]
Refresh the working copy of the file(s) from their history files. "co" is a synonym for "checkout".
src cat [revision] [file…]
Send the specified revision of the files to standard output.
src status [-a] [file…]
"A" = added, "=" = unmodified, "M" = modified, "!" = missing, "?" = not tracked, "I" = ignored, "L" = locked (recover with "src checkout"). The "A" and "L" statuses should only occur if you have used RCS directly on a file. Normally "?" and "I" files are not listed; this changes if you either give the -a switch or specify which files to look at. "st" is a synonym for "status".
src tag [list|-l|create|-c|delete|del|-d] [name] [revision] [file…]
List tags, create tags, or delete tags. Create/delete takes a revision, defaulting to the current branch tip. List to all revisions.
src branch [list|-l|create|-c|delete|del|-d] [name] [file…]
List, create, or delete branches. When listing, the active branch is first in the list. The default branch is "trunk". Create/delete takes a singleton revision, defaulting to the current branch tip. List defaults to all revisions, including 0 (the trunk root phantom revision).
src rename [tag|branch] [oldname] [newname] [file…]
Rename a tag or branch. Refuses to step on an existing symbol or rename a nonexistent one. "rn" is a synonym for "rename".
src list [revision-range] [file…]
Sends summary information about the specified commits to standard output. The summary line tagged with "*" is the state that the file would return to on checkout without a revision-spec. "li" is a synonym for "list".
src log [revision-range] [file…]
Sends log information about the specified commits to standard output.
src diff [revision-range] [file…]
Sends a diff listing to standard output. With no revision spec, diffs the working copy against the last version checked in. With one revno, diffs the working copy against that stored revision; with a range, diff between the beginning and end of the range. "di" is a synonym for "diff".
src ls
List all registered files.
src visualize
Emit a DOT visualization of repository structures. To use this, install the graphviz package and pipe the output to something like "dot -Tpng | display -". "vis" is a synonym for "visualize".
src move old new
Rename a workfile and its history. Refuses to step on existing workfiles or histories. "mv" is a synonym for "move".
src copy old new
Copy a file and its master. Refuses to step on existing files or masters. "cp" is a synonym for "copy".
src fast-export [revision-range] [file…]
Export one or more projects as a Git fast-import stream. The committer identification is copied from your Git configuration.
src fast-import [-p] [files…]
Parse a git-fast-import stream from standard input. The modifications for each individual file become separate SRC histories. Mark, committer and author data, and mark cross-references to parent commits, are preserved in RFC-822-style headers on log comments unless the -p (plain) option is given, in which case this metadata is discarded. Give arguments to restrict the files imported.
src release [file…]
Release locks on files. This is never necessary in a normal workflow, which will be repeated edit-commit cycles, but it may be handy if you have to interoperate with other tools that expect RCS masters to be in their normal (unlocked) state.
src version
Report the versions of SRC, the underlying Python, and the back end.

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.

SRC takes over the little-used "description" field of RCS (and SCCS) master files to store some state that makes status checks faster. If you try to use SRC to edit a pre-existing RCS- or SCCS-registered file with a non-empty description field, SRC will refuse to step on the old description; you must clear it manually.

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.

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".

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:

  • all commands relating to tags and branches throw an error.
  • src cat does not necessarily pipe out binary data correctly.

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.


These will be of interest mainly to developers.

A -d (debug) option before the main command word turns on debugging messages; it can be repeated for higher debugging levels.

A -S (sandbox) option can be used to set the repository directory to something other than its default of ".src".

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.

If you wish to use the RCS support, 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, the CSSC (Compatibly Stupid Source Control) system must be installed and accessible in your path.

The rcs-fast-import(1) tool at version 1.0 or later is required to support the src fast-import command.


Branch deletions change the revision numbers of revisions downstream of the branch join. This behavior may change in a future release.

The SCCS backend has a Y2.1K problem that SRC cannot effectively work around and will probably not be fixed.


Report bugs to Eric S. Raymond <>. The project page is at


rcs(1), rcs-fast-import(1), dot(1).