bash - Read from two files line by line and process them simultaneously

Question

Hello everyone I'm very new to the game so my question is probably rather simple but I'm stuck at this for a long time. I want to process two files from two list of files simultaneously line by line.

I'm trying currently:

 read file1 && read file2; 
    do 
    echo "$file1 and $file2"
    done 

The echo is of course just a spaceholder for the rest of the script but i didn't manage to get any variables out of the read operation.

Answer 1

You need two separate file descriptors to read from two files at once. One of them can be standard input.

while IFS= read -r line1 && IFS= read -r line2 <&3; do
  echo "File 1: $line1"
  echo "File 2: $line2"
done < file1 3< file2