Question

I am trying to create a shell script that pulls a line from a file and checks another file for an instance of the same. If it finds an entry then it adds it to another file and loops through the first list until the it has gone through the whole file. The data in the first file looks like this –

[e-mail];
[e-mail];
and so on   

The other file in which I am looking for a match and placing the match in the blank file looks like this –

12334    [e-mail];
32213    [e-mail];

I want it to retain the numbers as well as the matching data. I have an idea of how this should work but need to know how to implement it.

My Idea

#!/bin/bash
read -p "enter first file name:" file1
read -p "enter second file name:" file2
FILE_DATA=( $( /bin/cat $file1))
FILE_DATA1=( $( /bin/cat $file2))
for I in $((${#FILE_DATA[@]}))
     do 
     echo $FILE_DATA[$i] | grep $FILE_DATA1[$i] >> output.txt
     done

I want the output to look like this but only for addresses that match –

12334 [e-mail];
32213 [e-mail];

Thank You

Answer 1

Read line by the file1.txt file and assign the line to var ADDR. grep file2.txt with the content of var ADDR and append the output to file_result.txt.

(while read ADDR; do grep "${ADDR}" file2.txt >> file_result.txt ) < file1.txt