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

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

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