Linux/Unix shell script to number the lines of a file

Bash Shell script list file content along line numbers

How can I display line numbers of a file. This can be achieved in Linux and Unix using many commands such as cat, nl, sed etc. In this post we will see how to write a script to display line numbers as well as with commands

Example1: Display line numbers using cat

cat -n filename.txt

Example2: Save a file with line numbers included in the file

cat -n filename.txt > file2.txt

Example3: Display line number of a file along the content using nl command

nl filename.txt

Example4: How can I count number of lines in a file?

cat filename.txt | wc -l

Example5: Display line numbers using sed command.

sed = tem.txt | sed ‘N;s/\n/\t/’

Through Shell script

#!/bin/bash

j=0

for i in `cat filename.txt`

do

let j+=1

echo "$j $i"

done

Please feel free to add your own way of listing file content along with line numbers.