Shell Programming and Scripting

#! /bin/bash
while read num
do
    grep -q $num data.txt
    if [ $? -ne 0 ]
    then
        <run_command>
    fi
done < num.txt

while read line
do
    grep "$line" data.txt > /dev/null
    if [ $? -eq 0 ]
    then
        echo "$line number present in data file"
    else
        echo "$line number not present in data file"
        <<< execute the command u need >>>
    fi
done<num.txt

while read A
do
        grep $A data.txt > /dev/null
        [ $? -ne 0 ] && echo "Run a command"
done < num.txt

grep -f num.txt data.txt

for i in `cat num.txt`
do
search=`grep "$i" data.txt`
ret_cd=$?
if [ "$ret_cd" -gt 0 ]
then
echo "Match not found ,run a command"
fi
done

grep -vf num.txt data.txt | xargs -i echo "no match {}"