Help

1. man pico
   View the manual page (help) of the pico command. Press 'q' to quit.

File system

1. pwd
   Print the current working directory
2. cd
   Change directory to the user's home directory
3. cd /etc
   Change directory to /etc
4. ls
   List current directory content
5. ls -l
   List current directory content in long format
6. ls -l /etc
   List the content inside /etc directory in long format
7. mkdir x
   Create directory named "x"
8. rmdir x
   Remove directory named "x"
9. rm x
   Remove file named "x"
10. rm -rf x
    Remove directory x including all content inside forcefully (no prompts asked for confirmation)
11. cp filex filey
    Copy filex to filey
12. cp -a /etc/nginx /etc/nginx.backup
    Copy complete directory /etc/nginx to /etc/nginx.backup
13. mv x y
    Rename file or directory named 'x' to 'y'
14. chmod +x /usr/local/bin/myscript
    Change mode of the file to be an executable.
15. chmod 755 /usr/local/bin/myscript
    Change mode of the file so that
    1. read, write, exec permissions are set for the owner
    2. read and exec permissions are set for the users in the owning group
    3. read and exec permissions are set for all other users
16. chown userx:groupy filez
    Change the ownership of filez to user userx and user group groupy

System details

1. df -h
   Show file system usage (disk free)
2. du -h
   Show the current directory usage (disk usage)
3. free -m
   Show memory details
4. cat /proc/cpuinfo (or less /proc/cpuinfo)
   Show the cpu details
5. uptime
   Show system uptime and load average

Date/time

1. date
   Show date and time
2. timedatectl
   Show date, time and time synchronization details

User management

1. adduser kamal
   Add a new user to the system named "kamal"
2. useradd -m kamal
   Add a new user to the system named "kamal". Not interactive.
3. passwd
   Change the current user's password
4. passwd kamal
   Change the password of user named 'kamal'

Package management

1. dpkg -l
   List all installed packages
2. dpkg -l | grep vim
   Print only the lines containing word "vim" from the output of command "dpkg -l"
3. apt update
   Update package information from sources
4. apt upgrade
   Upgrade packages that can be upgraded
5. apt-cache search color picker
   Search for packages that matches the given text (color picker)
6. apt-cache show gpick
   Show the details of the package gpick
7. apt install gpick
   Install the package called gpick

Process management

1. ps x
   List all processes of the current user
2. ps xa
   List all system processes
3. ps xa | grep nginx
   Check if any process is running related to nginx
4. top
   Display system processes with additional details interactively. Press 'q' to quit.
5. kill PID
   Gracefully terminate a process with process id PID. PID of a process can be obtained from the ps command or top command.
6. kill -9 PID
   Forcefully terminate a process with the process id PID.

Service management

1. systemctl status nginx
   View the status of service nginx
2. systemctl start nginx
   If not running already, start nginx service
3. systemctl stop nginx
   Stop nginx service
4. systemctl is-enabled nginx
   Is nginx service configured to start at boot time?
5. systemctl enable nginx
   Enable nginx to start at boot time
6. systemctl disable nginx
   Stop nginx from starting at boot time