Super User is a question and answer site for computer enthusiasts and power users. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I need to diff two files (not two versions of the same file, they are however tracked by git, but that is unrelated) and I would like some colored output, how can I achieve that?

$ diff file_1 file_2

< <script ... >
<     // more code
< </script>


Above code shows me the difference between those files, however without any colors. For longer diffs that is hard to read.

Alternatively, is there a way for git (with which I do have nice color output) to diff two different files (not changes to a file)?

OSX (10.7.5)

share|improve this question
up vote 25 down vote accepted

Perl has a a lackluster colordiff wrapper for diff, but I prefer grc (generic colorizer).

With grc (generic colorizer), you can write your own wrappers for different types of commands or inputs (if you like that sort of thing).

Below, grc is running against /var/log/syslog (in the config, this file is set to a certain color scheme), where it highlights processes, pids, IPs and "connect"s.

Of course, it is recommended to use an alias so you don't forget:

alias diff="/usr/bin/grc /usr/bin/diff"

grc running against syslog

If you have git, you may just want to use that, which allows very robust diffing, even across branches.

git diff master:cogs/foo.txt branch:widgets/bar.txt

You do not have to use git diff within a repository, you can use it for just regular files.

git diff old.txt new.txt

As always, you can alias diff for ease of use.

alias diff="git diff"
share|improve this answer
yay for git diff – chrismarx Feb 4 '15 at 19:33
git diff should be at the top of your answer! +1 for pointing out that it works even outside of a repository. – Lucio Paiva Feb 7 '15 at 18:26
'git diff' does not work on generic files so aliasing diff to be 'git diff' can be harmful – Anton Chikin Apr 23 '15 at 23:13

When diffing files I almost always use vim:

vim -d file_1 file_2

It not only uses colours, it lines up the files so it's easier to see lines added/removed.

share|improve this answer
Wow... Vim is a beautiful thing. – WestonGanger May 23 at 16:30
@WestonGanger vim is indeed amazing, never ceases to impress me – Philip Kearns May 24 at 8:28

You can get git to diff two different files:

git diff branch1:full/path/to/foo.txt branch2:full/path/to/foo-another.txt
share|improve this answer

To build on the approved answer: grc works great for this. It is installable with brew and colorizes a number of terminal commands out of the box, diff being one of them. So...

brew install grc

...installs grc to your system. Then you need to set up your aliases, the brew caveat provides a solution. Simply add the following line to your .bashrc or similar.

source "`brew --prefix`/etc/grc.bashrc"

This will currently add the following aliases:

alias colourify="$GRC -es --colour=auto"
alias configure='colourify ./configure'
alias diff='colourify diff'
alias make='colourify make'
alias gcc='colourify gcc'
alias g++='colourify g++'
alias as='colourify as'
alias gas='colourify gas'
alias ld='colourify ld'
alias netstat='colourify netstat'
alias ping='colourify ping'
alias traceroute='colourify /usr/sbin/traceroute'
alias head='colourify head'
alias tail='colourify tail'
alias dig='colourify dig'
alias mount='colourify mount'
alias ps='colourify ps'
alias mtr='colourify mtr'
alias df='colourify df'
share|improve this answer

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .