How to display a specified line of a file or command result on Linux (sed, awk)

Learn how to use Linux commands (sed, ʻawk`) to display a specified line of a file or command result.

environment

• OS:CentOS Linux release 8.1.1911

[demo@centos8 test]$ cat /etc/redhat-release
CentOS Linux release 8.1.1911 (Core)
[demo@centos8 test]$

1. How to display the specified line in the file

There is a file (ʻa01.txt`).

a01.txt

1111 2222 3333 4444 a
2222 3333 4444 5555 b
3333 4444 5555 6666 c
4444 5555 6666 7777 d
5555 6666 7777 8888 e

1.1. Display line n

To display the ** 3rd line ** of the file (ʻa01.txt`), you can display it with the following command.

sed -n 3p a01.txt

Execution result

[demo@centos8 test]$ sed -n 3p a01.txt
3333 4444 5555 6666 c
[demo@centos8 test]$

You can also display it with the following command.

awk 'NR==3' a01.txt

Execution result

[demo@centos8 test]$ awk 'NR==3' a01.txt
3333 4444 5555 6666 c
[demo@centos8 test]$

1.2. Display lines m to n

To display ** 2nd to 4th lines **, use the following command.

sed -n '2,4p' a01.txt

Execution result

[demo@centos8 test]$ sed -n '2,4p' a01.txt
2222 3333 4444 5555 b
3333 4444 5555 6666 c
4444 5555 6666 7777 d
[demo@centos8 test]$

You can also display it with the following command.

awk 'NR==2,NR==4' a01.txt

Execution result

[demo@centos8 test]$ awk 'NR==2,NR==4' a01.txt
2222 3333 4444 5555 b
3333 4444 5555 6666 c
4444 5555 6666 7777 d
[demo@centos8 test]$

1.3 Display m and n lines

To display ** 2nd line ** and ** 4th line **, use the following command.

awk 'NR==2;NR==4' a01.txt

Execution result

[demo@centos8 test]$ awk 'NR==2;NR==4' a01.txt
2222 3333 4444 5555 b
4444 5555 6666 7777 d
[demo@centos8 test]$

1.4. Display the nth and subsequent lines

If you want to display ** all ** from the second line onward, you can display it with the following command.

tail -n +2 a01.txt

Execution result

[demo@centos8 test]$ tail -n +2 a01.txt
2222 3333 4444 5555 b
3333 4444 5555 6666 c
4444 5555 6666 7777 d
5555 6666 7777 8888 e
[demo@centos8 test]$

You can also display it with the following command. sed -n '2,$p' a01.txt

Execution result

[demo@centos8 test]$ sed -n '2,$p' a01.txt
2222 3333 4444 5555 b
3333 4444 5555 6666 c
4444 5555 6666 7777 d
5555 6666 7777 8888 e
[demo@centos8 test]$

awk 'NR>=2' a01.txt

Execution result

[demo@centos8 test]$ awk 'NR>=2' a01.txt
2222 3333 4444 5555 b
3333 4444 5555 6666 c
4444 5555 6666 7777 d
5555 6666 7777 8888 e
[demo@centos8 test]$

2. How to display the specified line of the command (using | (pipe))

The `ls -la'command displays:

Execution result

[demo@centos8 test]$ ls -la
16 in total
drwxrwxr-x 2 demo demo 66 June 14 16:13 .
drwx------.5 demo demo 159 June 14 15:38 ..
-rw-rw-r--1 demo demo 110 June 14 15:38 a01.txt
-rw-rw-r--1 demo demo 56 June 14 14:48 a02.txt
-rw-rw-r--1 demo demo 111 June 14 14:50 b01.txt
-rw-rw-r--1 demo demo 55 June 14 14:51 b02.txt
[demo@centos8 test]$

By connecting the commands with a pipe, you can input the sed and ʻawk` commands.

2.1. Display the nth line

To display the ** 4th line ** of the command result, you can display it with the following command.

ls -la | sed -n 4p

Execution result

[demo@centos8 test]$ ls -la | sed -n 4p
-rw-rw-r--1 demo demo 110 June 14 15:38 a01.txt
[demo@centos8 test]$

ls -la | awk 'NR==4'

Execution result

[demo@centos8 test]$ ls -la | awk 'NR==4'
-rw-rw-r--1 demo demo 110 June 14 15:38 a01.txt
[demo@centos8 test]$

2.2. Display lines m to n

To display the ** 4th to 6th lines ** of the command result, you can display it with the following command.

ls -la | sed -n '4,6p'

Execution result

[demo@centos8 test]$ ls -la | sed -n '4,6p'
-rw-rw-r--1 demo demo 110 June 14 15:38 a01.txt
-rw-rw-r--1 demo demo 56 June 14 14:48 a02.txt
-rw-rw-r--1 demo demo 111 June 14 14:50 b01.txt
[demo@centos8 test]$

ls -la | awk 'NR==4,NR==6'

Execution result

[demo@centos8 test]$ ls -la | awk 'NR==4,NR==6'
-rw-rw-r--1 demo demo 110 June 14 15:38 a01.txt
-rw-rw-r--1 demo demo 56 June 14 14:48 a02.txt
-rw-rw-r--1 demo demo 111 June 14 14:50 b01.txt
[demo@centos8 test]$

2.3 Display m and n lines

To display the ** 4th line ** and ** 6th line ** of the command result, you can display them with the following command.

ls -la | awk 'NR==4;NR==6'

Execution result

[demo@centos8 test]$ ls -la | awk 'NR==4;NR==6'
-rw-rw-r--1 demo demo 110 June 14 15:38 a01.txt
-rw-rw-r--1 demo demo 111 June 14 14:50 b01.txt
[demo@centos8 test]$

2.4. Display the nth and subsequent lines

If you want to display all ** after the ** 4th line of the command result, you can display it with the following command.

`ls -la | tail -n +4'

Execution result

[demo@centos8 test]$ ls -la | tail -n +4
-rw-rw-r--1 demo demo 110 June 14 15:38 a01.txt
-rw-rw-r--1 demo demo 56 June 14 14:48 a02.txt
-rw-rw-r--1 demo demo 111 June 14 14:50 b01.txt
-rw-rw-r--1 demo demo 55 June 14 14:51 b02.txt
[demo@centos8 test]$

ls -la | sed -n '4,$p'

Execution result

[demo@centos8 test]$ ls -la | sed -n '4,$p'
-rw-rw-r--1 demo demo 110 June 14 15:38 a01.txt
-rw-rw-r--1 demo demo 56 June 14 14:48 a02.txt
-rw-rw-r--1 demo demo 111 June 14 14:50 b01.txt
-rw-rw-r--1 demo demo 55 June 14 14:51 b02.txt
[demo@centos8 test]$

ls -la | awk 'NR>=4'

Execution result

[demo@centos8 test]$ ls -la | awk 'NR>=4'
-rw-rw-r--1 demo demo 110 June 14 15:38 a01.txt
-rw-rw-r--1 demo demo 56 June 14 14:48 a02.txt
-rw-rw-r--1 demo demo 111 June 14 14:50 b01.txt
-rw-rw-r--1 demo demo 55 June 14 14:51 b02.txt
[demo@centos8 test]$

that's all