How to Read File Lines in Bash

1. Read File Line by Line in Bash With read Command
2. Read File Line by Line in Bash With IFS and -r Option

This tutorial reads a file line by line in a bash script with the read command.

Here is the content of the text file that we will use.

 john\n ,
james\n ,
joe,
jack,
jill

Read File Line by Line in Bash With read Command

names.txt file is redirected to the while loop. The read command processes each line in the file and assigns it to the p variable, and the echo command displays it. Once all lines are processed, the while loop stops. The read command ignores the leading whitespaces, which can be misleading in some cases.

printf "Names\n"
while read p;
do
    echo "$p"
done <names.txt

Output:

Names
johnn ,
jamesn ,
joe,
jack,
jill

Read File Line by Line in Bash With IFS and -r Option

By default, the read command removes all leading whitespaces and interprets the backslash as an escape character. We add the -r option to disable backslash escaping, and to disable trimming whitespaces, so that the internal field separator(IFS) is cleared.

printf "Names\n"
while IFS= read -r line; do
    printf '%s\n' "$line"
done < names.txt

Output:

Names
 john\n ,
james\n ,
joe,
jack,
jill