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up vote 3 down vote favorite
1

I'd like to use diff as described here and in the documentation I see when I type man diff. However, when I type diff, what I get is this:

~ ❯❯❯ diff
usage: git diff --no-index <path> <path>

Similarly when I try to use diff, I get git errors because -rq is supported in man diff but not by git diff:

~ ❯❯❯ diff -rq ~/ ~/Desktop
fatal: invalid diff option/value: -rq

I'm using Prezto and hub which both help with git productivity, but neither creates an alias that doesn't at least start with g, as far as I can tell.

I've run a few scripts like this to try to find something that's defining diff to git diff but to no avail.

How do I fix this/find what's causing it/override it?

Edit

Ran type diff:

diff is a shell function
diff is /usr/bin/diff
share|improve this question
    
Run type diff and post the output. – Michael Homer yesterday
2  
And I suspect it will be github.com/sorin-ionescu/prezto/blob/master/modules/utility/… – Michael Homer yesterday
    
@MichaelHomer Added. That does look right to me. – Ben Saufley yesterday
    
I don't know how you tell prezto not to do that, but worst case you can just hack it out. – Michael Homer yesterday
1  
IN FACT! I ran brew install colordiff and now diff runs colordiff, which is an actual diff-based thing. – Ben Saufley yesterday

2 Answers 2

up vote 4 down vote accepted

This seems to be from prezto defining a function overriding diff. It may well have a way of disabling that, but I don't know what it is. You have a few options:

  • /usr/bin/diff or command diff will both run the diff command, rather than the function.
  • unset -f diff will remove the diff function. You could put that in your shell configuration.
  • As you've found, if colordiff is installed it will be used in preference to git diff by the function.
  • Finally, you can remove or rename the function from that file itself.

This really seems like a misfeature in prezto.

share|improve this answer
1  
Nailed it. Thanks Michael! – Ben Saufley yesterday
    
certainly a good example of the ills of global scope and naming collisions – Michael Durrant yesterday
up vote 1 down vote

I would use an function like this

$ diffit () {
command diff $1 $2
}

A function over an alias as there are parameters

Usage: diffit file1 file2

You could put it in your .bashrc
Personally I keep my collection of functions in .bash_functions and in .bashrc I have

test -f ~/.bash_functions.sh && . $_
share|improve this answer
    
Just make it command diff "$@". – Arthur2e5 yesterday

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