Name

colordiff — a tool to colorize diff output

Synopsis

colordiff [diff options] [colordiff options] {file1} {file2}

Description

colordiff is a wrapper for diff and produces the same output as diff but with
coloured syntax highlighting at the command line to improve readability. The
output is similar to how a diff-generated patch might appear in Vim or Emacs
with the appropriate syntax highlighting options enabled. The colour schemes
can be read from a central configuration file or from a local user ~
/.colordiffrc file.

colordiff makes use of ANSI colours and as such will only work when ANSI
colours can be used - typical examples are xterms and Eterms, as well as
console sessions.

colordiff has been tested on various flavours of Linux and under OpenBSD, but
should be broadly portable to other systems.

Usage

Use colordiff wherever you would normally use diff, or instead pipe output to
colordiff:

For example:

$ colordiff file1 file2
$ diff -u file1 file2 | colordiff

You can pipe the output to 'less', using the '-R' option (some systems or
terminal types may get better results using '-r' instead), which keeps the
colour escape sequences, otherwise displayed incorrectly or discarded by
'less':

$ diff -u file1 file2 | colordiff | less -R

If you want to force disable colour escape sequences (for example pipe the
output to patch), you can use option '--color=no' to do so:

$ diff -u file1 file2 | colordiff --color=no | patch -p0 -d another-working-dir

If you have wdiff installed, colordiff will correctly colourise the added and
removed text, provided that the '-n' option is given to wdiff:

$ wdiff -n file1 file2 | colordiff

You may find it useful to make diff automatically call colordiff. Add the
following line to ~/.bashrc (or equivalent):

alias diff=colordiff

Any options passed to colordiff are passed through to diff except for the
colordiff-specific option 'difftype', e.g.

colordiff --difftype=debdiff file1 file2

Valid values for 'difftype' are: diff, diffc, diffu, diffy, wdiff, debdiff;
these correspond to plain diffs, context diffs, unified diffs, side-by-side
diffs, wdiff output and debdiff output respectively. Use these overrides when
colordiff is not able to determine the diff-type automatically.

Alternatively, a construct such as 'cvs diff SOMETHING | colordiff' can be
included in ~/.bashrc as follows:

function cvsdiff () { cvs diff $@ | colordiff; }

Or, combining the idea above using 'less':

function cvsdiff () { cvs diff $@ | colordiff |less -R; }

Note that the function name, cvsdiff, can be customized.

By default colordiff returns the exit code of the underlying diff invocation
(if there is one), but there are some circumstances where it is useful to force
colordiff's exit code to be zero: to do this use the option '--fakeexitcode':

colordiff --fakeexitcode ...

Files

/etc/colordiffrc

    Central configuration file. User-specific settings can be enabled by
    copying this file to ~/.colordiffrc and making the appropriate changes.

colordiffrc-lightbg

    Alternate configuration template for use with terminals having light
    backgrounds. Copy this to /etc/colordiffrc or ~/.colordiffrc and customize.

colordiffrc-gitdiff

    Alternate configuration template for use with terminals having dark
    backgrounds, with colour defaults set to match the output of 'git diff'.
    Copy this to /etc/colordiffrc or ~/.colordiffrc and customize.

Bugs

Bug reports and suggestions/patches to <davee@sungate.co.uk> please.

