Find content of one file from another file in UNIX

Question

I have 2 files. First file contains the list of row ID\'s of tuples of a table in the database. And second file contains SQL queries with these row ID\'s in \"where\" clause

Answer 1

## reports any lines contained in < file 1> missing in < file 2>

IFS=$(echo -en "\n\b") && for a in $(cat < file 1>); 
do ((\!$(grep -F -c -- "$a" < file 2>))) && echo $a; 
done && unset IFS

or to do what the asker wants, take off the negation and redirect

(IFS=$(echo -en "\n\b") && for a in $(cat < file 1>); 
do (($(grep -F -c -- "$a" < file 2>))) && echo $a; 
done && unset IFS) >> < file 3>