rake bash completion

rake_completion.sh

# bash completion for rake
# Installation: cat rake_completion.sh >> ~/.bashrc
# Or, maybe: cat rake_completion.sh > /etc/bash_completion.d/rake

# checksecs is the number of seconds between checking for new rake tasks
checksecs=600

export COMP_WORDBREAKS=${COMP_WORDBREAKS/\:/}

if [[ "`which md5`" != "" ]]; then
  UID_BIN="md5"
elif [[ "`which md5sum`" != "" ]]; then
  UID_BIN="md5sum"
else
  UID_BIN="base64"
fi

_output_cache_rakefile(){
  local cachefile=$1
  date +"%s" > "$cachefile"
  rake -T 2>/dev/null | cut -d" " -f2 >> "$cachefile"
}

_check_rakefile() {
  if [ ! -e Rakefile ]; then
    return
  fi

  local cachefile=/tmp/rake_completion_`echo $PWD | $UID_BIN | cut -d" " -f1`
  if [ ! -e "$cachefile" ]; then
    _output_cache_rakefile $cachefile
  else
    local timestamp_diff=`expr \`date +"%s"\` - \`cat $cachefile | head -n 1\``
    if [ $timestamp_diff -gt $checksecs ]; then
      rm $cachefile
      _output_cache_rakefile $cachefile
    fi
  fi

  local tasks=$(tail -n +2 $cachefile)
  COMPREPLY=( $(compgen -W "${tasks}" -- "${COMP_WORDS[$COMP_CWORD]}") )
}
complete -F _check_rakefile -o default rake