#!/bin/bash



# cmp_dir - program to compare two directories



# Check for required arguments

if [ $# -ne 2 ]; then

  echo "usage: $0 directory_1 directory_2" 1>&2

  exit 1

fi



# Make sure both arguments are directories

if [ ! -d "$1" ]; then

  echo "$1 is not a directory!" 1>&2

  exit 1

fi



if [ ! -d "$2" ]; then

  echo "$2 is not a directory!" 1>&2

  exit 1

fi



# Process each file in directory_1, comparing it to directory_2

missing=0

while IFS= read -r -d $'0' filename

do

  fn=${filename#$1}

  if [ ! -f "$2/$fn" ]; then

      echo "$fn is missing from $2"

      missing=$((missing + 1))

  fi

done < <(find "$1" -type f -print0)



echo "$missing files missing"

Note that I have added double-quotes around $1 and $2 at various places above to protect them shell expansion. Without the double-quotes, directory names with spaces or other difficult characters would cause errors.

The key loop now reads:

while IFS= read -r -d $'0' filename

do

  fn=${filename#$1}

  if [ ! -f "$2/$fn" ]; then

      echo "$fn is missing from $2"

      missing=$((missing + 1))

  fi

done < <(find "$1" -type f -print0)

This uses find to recursively dive into directory $1 and find file names. The construction while IFS= read -r -d $'0' filename; do .... done < <(find "$1" -type f -print0) is safe against all file names.

basename is no longer used because we are looking at files within subdirectories and we need to keep the subdirectories. So, in place of the call to basename, the line fn=${filename#$1} is used. This just removes from filename the prefix containing directory $1.

Problem 2

Suppose that we match files by name but regardless of directory. In other words, if the first directory contains a file a/b/c/some.txt, we will consider it present in the second directory if file some.txt exists in any subdirectory of the second directory. To do this replace the loop above with:

while IFS= read -r -d $'0' filename

do

  fn=$(basename "$filename")

  if ! find "$2" -name "$fn" | grep -q . ; then

      echo "$fn is missing from $2"

      missing=$((missing + 1))

  fi

done < <(find "$1" -type f -print0)