# Linux Basic Commands #

- Update Linux built-in package
    - ``` sudo apt-get update ```
- Install software
    - ``` sudo apt install package_name ```
- Uninstall software
    - ``` sudo apt-get purge package_name ```
- List of file & folder
  - ``` ls ``` or ``` ls -l ```
- Change directory to root
  - ``` cd / ```
- Change directory to previous folder
  - ``` cd .. ``` or ``` cd - ```
- Change to super user (root)
  - ``` sudo su ```
- Change to another user
  - ``` su user_name```
- To check present working directory
  - ``` pwd ```
- Create file single or multiple
  - ``` touch a.txt b.txt ``` ( It will create two file "a.txt" & "b.txt" in present working directory )
- Create a new copy of "a.txt" as "a_backup.txt"
  - ``` cp a.txt a_backup.txt ``` ( We can also decleare directory with file name. Such as /home/a_backup.txt )
- Create a new copy of "a" folder
  - ``` cp a -r a_backup ``` ( -r Recursively create copy of folder and it's file )
- Delete "a.txt" file
  - ``` rm a.txt ```
- Delete "a" folder
  - ``` rm -r a ``` ( -r Recursively delete folder and it's file )
  - ``` rm -rf a ``` ( f Forcefully delete folder )
- Restore or move a file from another directory to current working directory
  - ``` mv /home/a_backup.txt a.txt ```
- History check
  - ``` history ```
- Storage memory check
  - ``` df -hT ```
- Free ram check
  - ``` free -mh ```
- Create new user for computer login
  - ``` adduser new_name ```
- Check user list ( Need to be in root directory )
  - ``` cat /etc/passwd ```
- Change password for given username ( If username will not given, it will change current username password )
  - ``` sudo passwd username ```
- It will show the detail of a command
  - ``` man command_name ```  Example: ``` man cat ```
- Delete user and it's file.
  -  ``` sudo userdel -r username ```  ( -r Recursively used for deleting it's file )
- Zipping a file
  - ``` zip to_desired_name.zip from_source_file_name ```
- Unzip file
  - ``` unzip zip_filename```
- Edit "a.txt" file from command line
  - ``` vim a.txt ```
    - Press I for insert or edit
    - Press ``` shift + : ```
    - Then type "wq" & press enter ( w = write & q = quit ) Changes will be saved
    - Then type "q!" ( Forcefully quit ) Changes will not be saved
- To see currently running task
  - ``` top ```