Day 3- Basics of Linux Commands (Part-2)

What are Linux Commands

1. To view what’s written in a file.

The Cat command is used to view the content of the file. It gives content as output.

Syntax: cat file_name

1. To remove a Directory/ File

The rm command is used to remove directories and files permanently without moving them to the trash directory. The rmdir command removes empty directories.

Syntax : rm file_name

To create a fruits.txt file and to view the content

ubuntu@ip-172-31-205-241:~$ vi fruits.txt
ubuntu@ip-172-31-205-241:~$ cat fruits.txt
Apple
Mango
Banana
Kiwi
Dragan
Guava

Add content in fruits.txt (One in each line) – Apple, Mango, Banana, Kiwi, Dragan, Guava.

 Apple
 Mango
 Banana
 Kiwi
 Dragan
 Guava
 ~
 ~
 ~

1. To Show only the top three fruits from the file.To show only the top three fruits we will use the head command. The Linux head command prints the first lines of one or more files to standard output. By default, it shows the first 10 lines. We can pass a -n, where n shows the specified number of line
   Syntax: head -n file_name
   
2. To Show only the bottom three fruits from the file to show only the bottom three fruits we will use the tail command. Tail is a command which prints the last few lines (10 lines by default) of a certain file.
   Syntax: tail -n file_name

To create another file Colors.txt and to view the content. Commands: vi Colors.txt cat Colors.txt

Add content in Colors.txt (One in each line) – Red, Pink, Blue, Orange, Purple, and Wine.

To find the difference between the fruits.txt and Colors.txt files. To find the difference between the content of two files we can use the diff command.

 ubuntu@ip-172-31-205-241:~$ diff fruits.txt colors.txt
 1,6c1,6
 < Apple
 < Mango
 < Banana
 < Kiwi
 < Dragan
 < Guava
 ---
 > Red
 > Pink
 > Blue
 > Orange
 > Purple
 > Wine
 ubuntu@ip-172-31-205-241:~$

1- echo – Print any text

ubuntu@ip-172-31-205-241:~$ echo “Hello World”
Hello World

2- grep – Find out the specific word, Find out the root word

Syntax: grep root /etc/passwd

  ubuntu@ip-172-31-205-241:~$ grep root /etc/passwd
 root:x:0:0:root:/root:/bin/bash

3- sort – Set all files in alphabetical order. for this, we use the colors.txt file and set this file alphabetically.

Syntax : sort colors.txt

 ubuntu@ip-172-31-205-241:~$ cat colors.txt
 Red
 Pink
 Blue
 Orange
 Purple
 Wine
 ubuntu@ip-172-31-205-241:~$ sort colors.txt
 Blue
 Orange
 Pink
 Purple
 Red
 Wine

4- hostname -i:- This command shows IP address of your machine.

ubuntu@ip-172-31-205-241:~$ hostname -i
172.31.205.241

5- ifconfig – This command shows details of ip address like netmask, prefix, interface, broadcast

Syntax: ifconfig

How to check the version of our operating system(os)

Syntax:- cat /etc/os-release

ubuntu@ip-172-31-11-66:~$ cat /etc/os-release
PRETTY_NAME="Ubuntu 22.04.2 LTS"
NAME="Ubuntu"
VERSION_ID="22.04"
VERSION="22.04.2 LTS (Jammy Jellyfish)"
VERSION_CODENAME=jammy
ID=ubuntu
ID_LIKE=debian
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
UBUNTU_CODENAME=jammy
ubuntu@ip-172-31-11-66:~$ 

1. How to install the software in Linux
   when you use this command then all packages are installed in that.
   Syntax: yum install httpd -y
2. We Check service is active or not by using this command
   Syntax: service httpd status
3. The command to activate the service
   Syntax: service httpd start
4. If you want to update the service
   Syntax: yum update httpd -y
5. If you want to remove the service
   Syntax: yum remove httpd -y
6. The command to stop the service
   Syntax: service httpd stop
7. Command to automatically start service in the backend
   Syntax: checkconfig httpd on
8. Command to off service if you have not needed
   Syntax: checkconfig httpd off
9. List of packages that are installed in our machine
   Syntax: yum list install

Thank you for reading! Hope you find this article helpful.