Shell Programming and Scripting

comm -3 /path/to/previous_list /path/to/actual_list | \
awk '
$0 ~ "^\t" {
   created[++created_idx]=$1;
   next;
}
{
   removed[++removed_idx]=$1 ;
   next;
}
END {

   if (created_idx > 0) {
      print "These files have been created"
      for (idx=1; idx <= created_idx; idx++)
         print "  " created[idx];
   } else {
      print "No files have been created"
   }

   if (removed_idx > 0) {
      print "These files have been removed"
      for (idx=1; idx <= removed_idx; idx++)
         print "  " removed[idx];
   } else {
      print "No files have been removed"
   }

} '

#! /bin/sh
# rt.sh

if [[ $# -ne 2 ]] ; then
echo "Need just 2 files to compare"
exit 1
fi ;

# Take the diff by ignoring the blank and whitespaces.
diff -b -w ${1} ${2} > ${1}.diff
        if [[ $? -eq 0 ]] ; then
        echo "No files were added/removed"
        else
        echo "Files were added/removed"
        fi ;

# Process the diff file.
# A line might look like 
# < text-which-went-out
# > text-which-came-in

while read line
do
        if [[ ${line:0:2} == "< " ]] ; then
        echo ${line:2} is removed. 
        fi ;

        if [[ ${line:0:2} == "> " ]] ; then
        echo ${line:2} is added.  
        fi ;

done < ${1}.diff

rm ${1}.diff