Find file names in other Bash files using grep - bash

Question

How do I loop through a list of Bash file names from an input text file and grep each file in a directory for each file name (to see if the file name is contained in the file) and output to text all file names that weren't found in any files?
#!/bin/sh
# This script will be used to output any unreferenced bash files
# included in the WebAMS Project
# Read file path of bash files and file name input
SEARCH_DIR=$(awk -F "=" '/Bash Dir/ {print $2}' bash_input.txt)
FILE_NAME=$(awk -F "=" '/Input File/ {print $2}' bash_input.txt)
echo $SEARCH_DIR
echo $FILE_NAME
exec<$FILE_NAME
while read line
do
echo "IN WHILE"
if (-z "$(grep -lr $line $SEARCH_DIR)"); then
echo "ENTERED"
echo $filename
fi
done

Answer 1

Save this as search.sh, updating SEARCH_DIR as appropriate for your environment:
#!/bin/bash
SEARCH_DIR=some/dir/here
while read filename
do
if [ -z "$(grep -lr $filename $SEARCH_DIR)" ]
then
echo $filename
fi
done
Then:
chmod +x search.sh
./search.sh files-i-could-not-find.txt

Answer 2

It could be possible through grep and find commands,
while read -r line; do (find . -type f -exec grep -l "$line" {} \;); done < file
OR
while read -r line; do grep -rl "$line"; done < file
-r --> recursive
-l --> files-with-matches(Displays the filenames which contains the search string)
It will read all the filenames present inside the input file and search for the filenames which contains the readed filenames. If it found any, then it returns the corresponding filename.

Answer 3

You're using regular parentheses instead of square brackets in your if statement.
The square brackets are a test command. You're running a test (in your case, whether a string has zero length or not. If the test is successful, the [ ... ] command returns an exit code of zero. The if statement sees that exit code and runs the then clause of the if statement. Otherwise, if an else statement exists, that is run instead.
Because the [ .. ] are actually commands, you must leave a blank space around each side.
Right
if [ -z "$string" ]
Wrong
if [-z "$string"] # Need white space around the brackets
Sort of wrong
if [ -z $sting ] # Won't work if "$string" is empty or contains spaces
By the way, the following are the same:
if test -z "$string"
if [ test -z "$string" ]
Be careful with that grep command. If there are spaces or newlines in the string returned, it may not do what you think it does.