Looping over pairs of values in bash

Question

I have 10 text files and I want to paste each file with its pair, such that I have 5 total files.

I tried the following:

for i in 4_1 5_         


        

Answer 1

the above did not work for me, but the following does read values in pairs from an ordered list

(can be more than pairs adding extra 'read-lines' :-)

while read x; do
  read y
  echo $x $y
done << '___HERE'
X1
Y1
X2
Y2
X3
Y3
___HERE

produces

X1 Y1
X2 Y2
X3 Y3