Auto-generate a list of ignore-dirs for ack from git ls-files

create-ack-ignores.sh

#!/bin/bash

# 
# This script serves as a useful base for generating a list of ignore-dirs 
# for ack. 
# It's slow to run (e.g. 30 sec on a 3000 file project on a 2010 MBA)
# and emits no output until complete.
#

# create the list of dirs tracked by git
GIT_DIR_FN=$(mktemp /tmp/create-ack-ignores_git.XXXXX) || exit 1
git ls-files | xargs -n 1 dirname | sort | uniq > $GIT_DIR_FN

# create the list of dirs tracked by ack
ACK_DIR_FN=$(mktemp /tmp/create-ack-ignores_ack.XXXXX) || exit 1
ack -f | xargs -n 1 dirname | sort | uniq > $ACK_DIR_FN 

# diff between git and ack dirs
ACK_DIR_DIFF_FN=$(mktemp /tmp/create-ack-ignores_diff.XXXXX) || exit 1

# list of dirs to exclude and the shortest path to exclude them
ACK_IGNORES_FN=$(mktemp /tmp/create-ack-ignores_ignore.XXXXX) || exit 1

diff -u $GIT_DIR_FN $ACK_DIR_FN > $ACK_DIR_DIFF_FN

# grab the dirs tracked by ack, but not by git
for line in $(tail -n +4 $ACK_DIR_DIFF_FN | ack '^\+'); do

  # strip the leading +
  line=${line:1}
  no_path_cs=$(echo $line | awk -F '/' '{print NF}')

  i=1
  while [[ $i -le $no_path_cs ]]; do
    path=$(echo $line | cut -d '/' -f 1-$i)

    ack $path $GIT_DIR_FN > /dev/null
    if [[ $? -eq 0 ]]; then
      # directory is tracked by git, descend
      i=$[$i+1]
    else
      # add directory to ignore list
      echo $line $path >> $ACK_IGNORES_FN
      break
    fi

  done

done

awk '{print $2}' $ACK_IGNORES_FN | sort | uniq | awk '{print "--ignore-dir=" $0}'