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.

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

Answer 2

You can use the paste command:

$ paste -d, file{1,2}.csv | while IFS=, read x y; do echo "$x:$y"; done
This:A
is:B
some:C
text.:D

Answer 3

You could try with the paste utility:

$ cat one
this
is
some
text
$ cat two
1
2
3
4
$ while read a b ; do echo $a -- $b ; done < <(paste one two)
this -- 1
is -- 2
some -- 3
text -- 4