CODEWITHSUNDEEP
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herrhansen
herrhansen

Reputation: 2423

calling git diff in pre-commit shell script

I try to put the output of 'git diff' into a variable in shell script to check if file has changed, but whenn running 'git diff file' in script I always get this output:

usage: git diff [--no-index] <path> <path>

here is what i am calling in the script 

#!/bin/sh
cd /path/to/repo
jsdiff=`git diff file.js`
echo "jsdiff: $jsdiff"

any ideas?

#!/bin/sh
#
# this script is always executed before the commit is typed
#
#

# Before commiting minify and compress javascript if changed

cd /path/to/repo/_js
jsdiff=`git diff main.js`
echo "jsdiff: $jsdiff"

#if [ "$jsdiff" != "" ]
#   then
        # compile js
#       ./googleClosureCompile.sh
#       echo "js minified"
#fi

exit 0;

Upvotes: 2

Views: 6402

Answers (1)

kirelagin
kirelagin

Reputation: 13616

You can get this error only if you run git diff in a directory which is not a repo, thus git diff thinks that you want to use it as a replacement for ordinary diff, so it wants two paths.

The problem here is that inside a hook $GIT_DIR is always set to .git so instead of trying to discover this directory git simply looks at .git. If you do cd somewhere even inside your repo git won't find this .git directory and it will think that it is not in a repo. So the easiest you can do is just avoid using cd in hooks.

Instead of 

cd /path/to/repo/_js
jsdiff=`git diff main.js`

do just

jsdiff=`git diff _js/main.js`

Also it's better to check git diff exit code. Here is how to do it:

#!/bin/sh

git diff --quiet _js/main.js || {
    # compile js
    # ...
}

Upvotes: 2

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