Here are the some important and most frequently used linux Command that every linux user must know, command like clear, sudo, mkdir, rm, touch, ls, cp, cd, cat, pwd, passwd, whereis, whoami, whatis, bc, du, df and other commands
Linux Commands
1. ls - List the content of the folder from which it runs
Syntax - ls
Example - ls -l and ls -a
2. mkdir - mkdir command is used to create new directory
Syntax -mkdir directory_name
Example - mkdir student
3. cat - To create file with content and can concatenate two or more file content
Syntax - cat > filename
Example - cat>student
4. touch - It is used to create file without content
Syntax - touch filename
Example - touch student
5. cp - It copies a file from one location to another location
Syntax - cp source_file destination_file
Example - cp student stud1
6. cd - It is used to change the directory
Syntax - cd directory_name
Example - cd Desktop
7. mv - It used to move a file from one location to another location
Syntax - mv source_file destination_file
Example - mv student1 student2
8. pwd - It print the present working directory with full path name from terminal
Syntax - pwd
Example - pwd
9. whereis - It is used to locate the sources and manual page of the command
Syntax - whereis command_name
Example - whereis cat
10. whatis - It is helpful to get brief information about linux commands
Syntax - whatis command_name
Example - whatis cp
11. which - It is used to locate executable file in the system
Syntax - which command_name
Example - which cpp python java
12. man - It provides online documentation for all the possible options with a command and its usages
Syntax - man command_name
Example - man cat
13. info - It provides online documentation for all the commands but in a better structured way
Syntax - info command_name
Example - info cp
14. whoami - It is used to find out the current user of the terminal
Syntax - whoami
Example - whoami
15. bc - It means basic calculator, It used for the basic calculation
Syntax - bc
Example - echo '2+2' | bc
16. grep - It searches the given file for lines containing a match to the given string or words
Syntax - grep word filename
Example - grep mv student
17. head - It prints the first 10 lines of the given file
Syntax - head filename
Example - head student.txt
18. tail - It print the last 10 lines of the given file
Syntax - tail filename
Example - tail student.txt
19. tac - It print the content of the given file in reverse order
Syntax - tac filename
Example - tac student.txt
20. echo - It print text on the standard output, However in an interactive script echo passes the message to the user through terminal
Syntax - echo Hello world
Example - echo Hello world
21. df - Report disk usages of file system useful for user as well as system administrator to keep track of their disk usages.
Syntax - df
Example - df
22. du - It estimate file space usages. df only report usages statistics on file system while du on the other hand measures directory content.
Syntax - du
Example - du
23. ps - It stands for process, It gives the status of running process with a unique ID called PID
Syntax - ps
Example - ps
24. alias - It is built in shell command that lets you assign name for a long command or frequently used command
Syntax - alias alias_name command
Example - alias q=ls
25. uname - It stands for unix name, It print detailed infromation about the machine name, operating system and kernel
Syntax - uname
Example - uname
26. sudo - It allows a permitted user to execute a command as the super user
Syntax - sudo command
Example - sudo passwd
27. su - It is used to run shell with substitute user and group IDs, It help to change login session's owner without the owner having to first logout of that session
Syntax - su username
Example - su username
28. history - It print the history of long list executed command in the terminal
Syntax - history
Example - history
29. passwd - It is used for changing the password, you must know the current password for the security reason
Syntax - passwd
Example - passwd
30. date - It print the current date and time on the standard output and can further be set
Syntax - date
Example - date
31. cal - It is used to display calendar of the present month or any other month
Syntax - cal [month] [year]
Example - cal 08 2001
32. clear - It is used to clear the terminal screen
Syntax - clear
Example - clear