bash - Reading lines from two files in one while loop

Question

I have a file, file1.csv containing:

This
is
some
text.

I am using while read line to cycle through each line, e.g.:

while read line; do
    echo $line
done < file1.csv

I have another file, with an identical number of lines, called file2.csv:

A
B
C
D

The data each line corresponds to data in the first file of the same line number.

• How can I modify the while loop, such so that it can print the corresponding line from file2.csv?

Answer 1

Use another FD.

while read line; do
  if ! read -u 3 line2
  then
    break
  fi
  echo "$line***$line2"
done < file1.csv 3< file2.csv