How to loop through lines in a file which contains * in each line

Question

I have a file that contains about 800 lines. All the lines contains 1 * character in it.

I need to loop through the lines in the file so I used the following simple for loop

for i in $(cat file_path); do echo $i; done

Unfortunately it did not work.

When I try it with another files but the lines in the file do not contains the * character, the loop is working fine.

How can I solve this?

Answer 1

You have some troubles with your code:

• Leaving variables and command substitution unquoted
• Using echo with arbitrary variable

You can fix them by using while loop:

while IFS= read -r line <&3; do
  { printf '%s\n' "$line"; } 3<&-
done 3< file

[ -z "$line" ] || printf %s "$line"

A note that using while loops to process text files is considered bad practice in POSIX shell.

Answer 2

You can use while:

while read line; do echo "$line"; done < test.txt

or define separate character IFS:

SAVEIFS=$IFS; IFS="\n"; for i in $(cat test.txt); do echo "$i"; done; IFS=$SAVEIFS

Answer 3

You have to use the following format :

#!/bin/bash
SAVEIFS=$IFS
while IFS= read -r line <&3
do
    echo "$line"
done 3< myfile.txt
IFS=$SAVEIFS

Test is :

root@debian:/home/mohsen/test/shell# ./linebylibe.sh 
ff
dd
gg
tt
tt
ww
ee

And my myfile.txt is :

root@debian:/home/mohsen/test/shell# cat myfile.txt 
ff
dd
gg
tt
tt
ww
ee