I use while..do..done bash to read file line by line on a Linux system. The content Bash read file line by line. Bash script the essential for DevOps Roles. you can ref to Bash script tutorial.
To read a file line by line using Bash, you can use a combination of the while loop and the read command.
Examples Bash read file line by line
Example 1: Using bash to read file.txt file.
[huupv@huupv devopsroles]$ cat file.txt Huu 30 Phan 28 foo 00
The content bash_read_file.sh file
#!/bin/bash
#To take a filename as an argument
filename="$1"
while read -r name age
do
_NAME="$name"
_AGE="$age"
echo "Name read from file - ${_NAME}"
echo "${_NAME}: Age is - ${_AGE}"
done < "$filename"
To change mode execute and run the bash script
[huupv@huupv devopsroles]$ chmod +x bash_read_file.sh [huupv@huupv devopsroles]$ ./bash_read_file.sh file.txt
The screen terminal:
Name read from file - Huu Huu: Age is - 30 Name read from file - Phan Phan: Age is - 28 Name read from file - foo foo: Age is - 00
Example 2: Bash script read /etc/passwd file with fields: filed1 filed2 filed3 filed4 filed5 filed6 filed7
The content bash_read_file.sh file
#!/bin/bash #Another thing is to take a filename as an argument. filename="$1" IFSOLD=$IFS IFS=: while read -r field1 field2 field3 field4 field5 field6 field7 do #display fields in /etc/passwd file printf 'Username: %s \t Shell: %s \t Home Dir: %s\n' "$field1" "$field7" "$field6" done < "$filename" IFS=$IFSOLD
The while loop reads each line from the file using the read command. The IFS= read -r field command ensures that leading and trailing whitespaces are preserved in each line.
The screen output terminal:
Conclusion
Thought the article, you can use Bash read file line by line. I hope will this your helpful.
