Script to diff configuration files (INI-style)

config-diff.sh

#!/bin/bash

# Diffs 2 configuration files, sorting their content by sections to and key
# names to get a meaningful diff.

sed_escape() {
  sed 's/[][/\\.$^]/\\\0/g' <<<"$1"
}

read_section_sorted() {
  local file="$1"
  local section="$2"
  
  echo
  echo "$section"
  sed "$file" -n -e "
/^$(sed_escape "$section")/{
:loop
  n
  /^\[/q
  /^ *$/!p
b loop
}
" | sort -s
}

read_conffile_sorted() {
  grep -e '^\[' "$1" | sort -u | while read section; do
    read_section_sorted "$1" "$section"
  done
}

diff -u <(read_conffile_sorted "$1") <(read_conffile_sorted "$2")