pre-commit

pre-commit

#!/bin/sh
#
# In your git repo:
#   1. save this file as: .git/hooks/pre-commit
#   2. chmod 755 .git/hooks/pre-commit
#
# An hook script to normalize what is about to be committed.
# Called by "git commit" with no arguments.
# Removes trailing whitespace if it exists from files.
# Replaces multiple blank lines with single blank line in files.

# For files (not deleted) in the index
files=$(git diff-index --name-status --cached HEAD | grep -v ^D | cut -c3-)
echo "running .git/hooks/pre-commit"
if [ "$files" != "" ]
then
  for f in $files
  do

    # Only examine known text files
    if [[ "$f" =~ [.](coffee|rb)$ ]]
    then
      # Remove trailing whitespace if it exists
      if grep -q "[[:blank:]]$" $f
      then
        echo "stripped trailing whitespace in: $f"
        sed -i "" -e $'s/[ \t]*$//g' $f
        git add $f
      fi

      # Replace multiple blank lines with single blank line
      cat -s $f > "$f.tmp"
      diff --brief $f "$f.tmp" >/dev/null
      comp_value=$?
      if [ $comp_value -eq 1 ]
      then
        echo "squeezed multiple blank lines in: $f"
        mv "$f.tmp" $f
        git add $f
      else
        rm "$f.tmp"
      fi
    fi
  done
fi

@robmckinnon maybe also mention that once the file is saved as .git/hooks/pre-commit it should be made executable

chmod 755 .git/hooks/pre-commit