Read file line by line and perform action for each in bash

Question

I have a text file, it contains a single word on each line.

I need a loop in bash to read each line, then perform a command each time it reads a line, using the inpu

Answer 1

As an alternative, using a file descriptor (#4 in this case):

file='testfile.txt'
exec 4<$file

while read -r -u4 t ; do
    echo "$t"
done

Don't use cat! In a loop cat is almost always wrong, i.e.

cat testfile.txt | while read -r line
do
   # do something with "$line" here
done

and people might start to throw an UUoCA at you.