As a linux system admin , you use many command in your daily life . Some command which is used rarely and some are used commonly in your daily job life . In this article , i am going to describe 50 most popular linux commands . You can use these command through linux command line interface . These commands are very useful to understand  linux operating system . Any one who is preparing for Red Hat certification and interviews would also do well after practicing these commands .

50 most popular linux commands

1.  ls Command 

This command is used to list files and directory  .

2. mkdir Command

This command is used to create directory .

3. cp Command

cp is used to copy a file or directory from one location to another location .

you can use -r flag to copy a directory

4 . mv Command 

mv is used to move a file or directory . It is also used for rename in same working directory .

5 . touch Command 

touch is used for create a file .

To create a hidden file , just put dot(.) before your file name

6. useradd Command 

This is used to add a user in your system .

7. passwd Command

passwd is used to set a password of user

8. userdel Command 

userdel is used to delete user from your system.

9. su Command 

su is used for switch from one user to another user

you need password for switch to root user

10. ps Command

ps is used to provide information about currently running process .

11. cd Command

cd is used to change working directory

12. pwd Command

pwd print current working directory

13. rm Command

rm is used to remove a file or directory

14. mount Command 

mount command is used to mount a file system . For this first of all you should create a directory.

15. echo Command

echo is used for insert text in shell script . It is also used for print a string

16. cat Command

cat is used to view content of a file.

17. free Command

This command is used to display used, free memory in your system


18. top Command

top command displays top process in your system .

top command
19. kill Command

kill command is used to terminate a process .

kill -9 is used to kill currently running process.

20. grep Command

grep is used to search a given string in a file.

21. sar Command 

sar is used to report performance of various linux subsystem in real time. The following gives the statics of CPU 5 times with 2 second interval. You can read more about sar at Generate CPU, Memory Report Using SAR Command

sar command
22. chmod Command

chmod is used to change the permission of a file or directory

chmod command
23. uname Command

uname display import information about system such as kernel name,  host name, kernel release

24. ifconfig Command

ifconfig is used to view or configure network interface of your system

25. man Command

man displays man page of a specific command.

26. chown Command

chown used to change owner and group of a file.

27. netstat Command

netstat used to display network related information

28. df Command

df used to display disk space uses of file system.

df command
29.  tail Command

tail used to print last 10 lines of a file by default.

30. head Command

head used to print first 10 lines of a file by default.

31. clear Command

clear command is used to clear the trminal screen

32. rmdir Command

rmdir used to remove empty directory. Here linux is an empty directory.

33. shutdown Command

shutdown used to power off the system. To shutdown the system after 5 min use the command given below –

To reboot the system , use the command given below –

34. locate Command 

locate is used to find the location of a specific file.

35. less Command 

less is very useful command while you are viewing large log file. It is used to view the file instead of opening the file

36. more Command

more command is used to view the content of a file one screen at a time.

37. vmstat Command

vmstat used to report virtual memory statistics .

38. lsof Command

lsof is used to list all open files

lsof command
39. id Command

id used to print information about current user.

40. wget Command

wget is used to download software, music , video from internet.

41. yum Command

yum is used to install package with their dependencies.

42. rpm Command

rpm is used to install a package in linux.

43. file Command

file command is used to determine the type of file in linux

44. wc Command

wc is used to print number of lines, words and bytes of files.

45. chkconfig Command

chkconfig is used to update and queries runlevel information for the system services

46. diff Command 

diff command is used to find difference between two files.

47. uptime Command

uptime used to tell how long the system has been running.

48. ping Command

ping is used to check network connectivity using ICMP

49. date command

date is used to print or set date and time of system

After changing the time and date, synchronize date and time with hardware clock. utc is used for universal time.

50. tar Command

tar command is used to create extract tar archive file.

In this article i describe 50 most popular linux commands . I hope this is useful for you.