Shell Programming and Scripting

awk ' BEGIN {RS = ""; FS = "(\n)| ( )"}  # set the record separator as ""

        # save the first file name and 4th field of it in an array 
        NR == FNR {   seen[$4] = 1; prefile = FILENAME }

        # test if the $4 in second file existing in the array or not
        NR != FNR  {
          nextf = FILENAME;
          if( $4 in seen)   seen[$4] = 0
          else      
             print $4 " found in " nextf " not found in " prefile
        }

        # print the field in first file but not in the nextfile
        END {
          for( ix in seen){
            if( seen[ix] == 1)
              print ix " found in " prefile " not found in " nextf
          }
        }
       '  file.abc  file.def

sed -n '/^name/p' a | awk '{print $2}' | sort > a.t
sed -n '/^name/p' b | awk '{print $2}' | sort > b.t
for i in `comm -23 a.t b.t`
do
echo "$i" is in a but not in b
done
echo
for i in `comm -13 a.t b.t`
do
echo "$i" is in b but not in a
done
rm a.t b.t