#!/bin/bash
#<pre><b>
# Script     : ddiff
# Version    : 1.1
# Author     : Roland Rashleigh-Berry
# Date       : 24-Nov-2006
# Purpose    : Production script to compare identically named files with those
#              in another directory (default is parent directory)
# SubScripts : none
# Notes      : Refer to documentation on diff (man diff). Note that this utility
#              has pattern matching and substitution in it to mask lines that
#              will always change for each run. You need to supply this to the
#              -i option. You should supply a regular expression and this would
#              normally start with the ^ character signifying the beginning of
#              a line. The rest of the line will be automatically ignored.
#              You can run this utility in quiet mode using option -q and then
#              it will only list the files where differences were found.
#              A check is performed to see if the file in the current directory
#              matches a file in the target directory and if there is no
#              matching file name then no comparison is done and no message will
#              be issued in that case. Use the "compdirs" script to find out
#              which files are extra or missing in the compared directories.
#
# Usage      : ddiff -i "^OUTPUT" *.LST > differ.txt
#              ddiff -i "^Report No" *.lis > differ.txt
#              ddiff -i "^Report No" -d /aaa/bbb/ccc *.lis > differ.txt
#              ddiff -i ^Report -q > changedfiles.txt
#===============================================================================
# OPTIONS:
#-opt- -------------------------------description-------------------------------
#  i   (value)  Ignore lines matching this regular expression
#  d   (value)  Other directory (defaults to parent directory ../)
#  q   (switch) Quiet mode to just list files where differences were found
#===============================================================================
# PARAMETERS:
#-pos- -------------------------------description-------------------------------
#  1   File(s) to compare with those in target directory
#===============================================================================
# AMENDMENT HISTORY:
# init --date-- mod-id ----------------------description------------------------
# rrb  08sep05         added -d option 
# rrb  12sep05         added -q option
# rrb  24nov06         only compare if file name exists in target directory
#===============================================================================
# This is public domain software. No guarantee as to suitability or accuracy is
# given or implied. User uses this code entirely at their own risk.
#===============================================================================

usage () {
  echo "Usage: ddiff -i <regular expression for lines to ignore> " 1>&2
  echo "             -d <specific directory if not ../ > -q <quiet mode> *.lis"
1>&2
  exit 1
}

# Default values for quiet mode, ignore lines and other directory
switchq=0
valuei=
valued='../'


# "case" statement for action to take on selected options
while getopts "i:d:q" param ; do
  case $param in
   "?") # bad option supplied
        usage
        ;;
   "i") # (value) Ignore these lines
        valuei=$OPTARG
        ;;
   "d") # (value) Other directory
        valued=$OPTARG
        ;;
   "q") # (value) Other directory
        switchq=1
        ;;
  esac
done


# make sure directory ends with a slash
valued=$(echo "$valued" | sed 's%[^/]$%&/%')

# shift to bring first parameter to position 1
shift $(($OPTIND - 1))


if [ $# -lt 1 ] ; then
  echo "Error: (ddiff) No files to compare supplied as a parameter" 1>&2
  usage
fi


for file in "$@" ; do
  if [ -e ${valued}$file ] ; then
    if [ $switchq -ne 1 ] ; then
    echo ; echo ; echo
    echo
'============================================================================================='
    echo " < = $file   > = ${valued}$file"
    echo
'============================================================================================='
    fi
    if [ -n "$valuei" ] ; then
      sed "s/${valuei}.*//"          $file > ~/file1_$$.tmp
      sed "s/${valuei}.*//" ${valued}$file > ~/file2_$$.tmp
    else
      cp          $file ~/file1_$$.tmp
      cp ${valued}$file ~/file2_$$.tmp
    fi
    if [ $switchq -ne 1 ] ; then
      diff -b ~/file1_$$.tmp ~/file2_$$.tmp
    else
      # quiet mode so route standard output to /dev/null
      # and report file name only if differences found
      diff -b ~/file1_$$.tmp ~/file2_$$.tmp 1> /dev/null
      rc=$?
      if [ $rc -eq 1 ] ; then
        echo "$file"
      fi
    fi
    rm -f ~/file1_$$.tmp ~/file2_$$.tmp
  fi
done

rm -f ~/file1_$$.tmp ~/file2_$$.tmp