Validation Git precommit hock

gistfile1.sh

#!/bin/sh

if git rev-parse --verify HEAD >/dev/null 2>&1
then
against=HEAD
else
# Initial commit: diff against an empty tree object
against=4b825dc642cb6eb9a060e54bf8d69288fbee4904
fi

files=( $(git diff --cached --name-only $against) )
for f in "${files[@]}"; do
  commit_file=$f

  filename=$(basename "$commit_file")
  ext="${filename##*.}"

  ##
  # TODO: Skip validations if binary content or enable
  # only for certain file extensions (.rb, .erb,...) and
  # files (Gemfile, Rakefile,...), respectively
  #

  ##
  # Collect line numbers of locations violating...
  #
  violations=false

  # End-of-line rule (only \n allowed)
  lines=( $(grep -n -IU $'\r' $commit_file | cut -f1 -d:) )
  if [ ${#lines[@]} -gt 0 ]; then
    violations=true
    echo
    echo "!!! End-of-line violations in '${commit_file}' !!!"
    for n in "${lines[@]}"; do
      echo "  line ${n}"
    done
  fi

  # Trailing whitespaces
  lines=( $(grep -n -E "\s+$" $commit_file | cut -f1 -d:) )
  if [ ${#lines[@]} -gt 0 ]; then
    violations=true
    echo
    echo "!!! Trailing whitespaces in '${commit_file}' !!!"
    for n in "${lines[@]}"; do
      echo "  line ${n}"
    done
  fi

  # Merge conflict markers
  lines=( $(grep -n -E "^(<{7}|={7}|>{7})" $commit_file | cut -f1 -d:) )
  if [ ${#lines[@]} -gt 0 ]; then
    violations=true
    echo
    echo "!!! Merge conflict markers in '${commit_file}' !!!"
    for n in "${lines[@]}"; do
      echo "  line ${n}"
    done
  fi

  # Active debugger commands
  # Restriction: Does not check for multi-line comments (=begin...=end)

  # bash:
  # a='apples, pears ; and bananas'
  # b='apples, pears # and bananas'
  # echo ${a%%;*}
  # echo ${b%%#*}

  # sed:
  # echo "$1" | sed 's/ *[#;].*$//g' | sed 's/^ *//'

  # Only check Ruby enabled sources (.rb, .erb) for debugger commands
  ruby_file_ext=(rb erb)

  if [[ ${ruby_file_ext[*]} =~ $ext ]]; then
    lines=( $( cat $commit_file | sed 's/ *[#;].*$//g' | sed 's/^ *//' | \
               grep -n -E "\bbinding\.pry\b|\bdebugger\b" \
               | cut -f1 -d:) )
    if [ ${#lines[@]} -gt 0 ]; then
      violations=true
      echo
      echo "!!! Debugger command(s) in '${commit_file}' !!!"
      for n in "${lines[@]}"; do
        echo "  line ${n}"
      done
    fi
  fi

  # TODO: Check .slim sources for Ruby/debugger statements
  # (Ruby statements enabled with preceding '-')

done


# Exist with error status if violations exist
if [ "$violations" = true ]; then
  exit 1;
fi