1. Linux Commands Help HANDS ON TRAINING Author: Muhammad Laique

2. Linux Commands AWS Linux Commands
A command is an instruction given by a user telling a computer to do something, such a run a single program or a group of linked programs.
Commands are generally issued by typing them in at the command line (the all-text display mode) and then pressing the ENTER key, which passes them to the shell.
The first word is the command itself, which tells the shell “what” to do. The remaining words are commands options. An option controls “how” the command is to be performed.
AWS Linux Commands

3. Linux Commands AWS Linux Commands
Shell is a UNIX term for the interactive user interface with an operating system.
The shell is the layer of programming that understands and executes the commands a user enters. In some systems, the shell is called a command interpreter.
The term shell derives its name from the fact that it is an outer layer of an operating system.
A shell is an interface between the user and the internal parts of the operating system (at the very core of which is the kernel).
AWS Linux Commands

4. Linux Commands
Shell
AWS Linux Commands

5. Linux Commands
AWS Linux Commands

6. Linux Commands
AWS Linux Commands

7. Linux Commands AWS Linux Commands User Name General User’s Symbol
Host Name
Home Directory
of the User
AWS Linux Commands

8. Linux Commands AWS Linux Commands Super User’s Symbol
Super user is also known as Root user
AWS Linux Commands

9. Linux Commands AWS Linux Commands ls
Lists the information about files and directories.
Syntax
ls directory-name
Options
ls –l (long/detailed form)
ls –lh (long and human readable form)
ls –a (lists all files, also hidden files)
ls –t (sort by time)
AWS Linux Commands

10. Linux Commands Symbol Meaning - File b Block Device c Special File d
File symbols which lists using ls command output.
Symbol
Meaning -
File b
Block Device c
Special File d
Directory l
Link s
Socket File
AWS Linux Commands

11. Linux Commands AWS Linux Commands cd
Command use to change working directory.
Syntax
cd /path/directory-name
Options
cd (Jump to old working directory)
cd OR cd ~ (Jump to home directory of login user)
cd (Jump to parent directory of current woking directory)
cd ../.. (Same as cd.. But jump two step back)
AWS Linux Commands

12. Linux Commands AWS Linux Commands pwd
Print the name of current working directory.
Syntax
AWS Linux Commands

13. Linux Commands AWS Linux Commands mkdir To create a new directory.
Syntax
mkdir directory-name
Options
mkdir -p (to make parent directory as we have needed)
AWS Linux Commands

14. Linux Commands AWS Linux Commands rmdir To remove empty directory.
Syntax
rmdir dir-name
AWS Linux Commands

15. Linux Commands AWS Linux Commands touch To create an empty file.
To update the access and modification time of existing file or directory.
Syntax
touch file-name
touch dir-name
AWS Linux Commands

16. Linux Commands AWS Linux Commands stat
To view the status of a file or directory.
Syntax
stat file-name
AWS Linux Commands

17. Linux Commands AWS Linux Commands file
This command is used to determine a file’s file type.
Synatx
file file-name
AWS Linux Commands

18. Linux Commands AWS Linux Commands rm To remove file or directory.
Synatx
rm file-name
rm -r dir-name
Options
rm -f (to remove a file forcefully)
rm -r (to remove a directory/recursively)
rm -rf (to remove a directory forcefully)
AWS Linux Commands

19. Linux Commands AWS Linux Commands mv
To move file or directory from one location to an other location.
Also used to rename file and directory.
Syntax
mv file-name /location
mv old-name new-name
AWS Linux Commands

20. Linux Commands AWS Linux Commands cat To view contents of file.
Also used to create new text file.
Syntax
cat file-name (to view the file contents)
cat > file-name (to create a text file)
cat >> file-name (to append the text existing file)
Ctrl+d (to save contents of the file)
Options
cat -n (to view contents of file with line numbers)
AWS Linux Commands

21. Linux Commands AWS Linux Commands cp
Use to copy the files and directories.
Syntax
cp file1 file2
cp -f file1 file2 (to copy file forcefully)
cp -r dir1 dir (to copy directory recursively)
AWS Linux Commands

22. Linux Commands AWS Linux Commands uname
Use to show the kernel name and other information.
Synatx
Options
uname -o (to show OS name)
Uname -r (to show kernel version)
Uname -v (to show kernel release)
uname -n (to show hostname)
AWS Linux Commands

23. Linux Commands AWS Linux Commands echo
To print the string on the screen.
Also used to create file.
Syntax
echo string to print
echo string to save > file-name
echo string to append >> file-name
AWS Linux Commands

24. Linux Commands AWS Linux Commands which
To locate the path of command or program.
Syntax
which command
which cp
AWS Linux Commands

25. Linux Commands AWS Linux Commands cal To display calendar. Syntax
Options
cal -y (to show the complete calendar)
cal -m (calendar start from Monday)
cal -j (to show Julian calendar)
cal (to show previous, current and next month calendar)
AWS Linux Commands

26. Linux Commands AWS Linux Commands wc
Print byte, word, and line counts.
Syntax
wc file-name
Options
wc -c (to count characters of file)
wc -w (to count words of file)
wc -l (to count lines of file)
AWS Linux Commands

27. Linux Commands AWS Linux Commands who
Print information about users who are currently logged in
Syntax
Options
who -H (out put with heading)
who -b (to show boot time)
who -r (to show current runlevel)
AWS Linux Commands

28. Linux Commands AWS Linux Commands whoami
Show current logged on user on terminal.
Syntax
AWS Linux Commands

29. Linux Commands AWS Linux Commands more
To display the contents of a file from top to bottom.
Syntax
more file-name
Navigation Keys
Enter key
Use to page down line by line
Space key
Use to page down page by page
AWS Linux Commands

30. Linux Commands AWS Linux Commands less
To display the contents of the file.
We can navigate the page up and down line by line and page by page
Syntax
less file-name
AWS Linux Commands

31. Linux Commands AWS Linux Commands head
To display the first part of the file.
Syntax
head file-name
Options
head -n (to show n (number) lines of file)
AWS Linux Commands

32. Linux Commands AWS Linux Commands tail
To display the last part of the file.
Syntax
tail file-name
Options
tail -n (to show n (number) lines of file)
tail -f (to follow the file updating)
AWS Linux Commands

33. Linux Commands AWS Linux Commands | Pipe line.
Redirect the output of one command into another command.
Syntax
commad1 | command2
ls -l | wc -l
ls -l /etc | less
AWS Linux Commands

34. Linux Commands AWS Linux Commands history
To view the commands line history.
Syntax
history file-name
Options
history -c (clear the history)
history -w file-name (to save the history in text file)
AWS Linux Commands

35. Linux Commands AWS Linux Commands tac
To view the contents of file in reverse order.
Syntax
tac file-name
tac > file-name
tac >> file-name
AWS Linux Commands

36. Linux Commands AWS Linux Commands grep To matching pattern.
To search the given pattern in file
Syntax
grep pattern file-name
grep pattern file-name1 file-name2
cat file-name | grep pattern
Options
grep -i (To ignore case sensitivity)
grep --color (To high light pattern)
AWS Linux Commands

37. Linux Commands AWS Linux Commands tr
To translate the contents of file from lower case to upper case and vise versa.
Syntax
tr 'a-z' 'A-Z' < file-name
cat file-name | tr 'a-z' 'A-Z'
cat file-name | tr 'a-z' 'A-Z' > new-file
AWS Linux Commands

38. Linux Commands AWS Linux Commands hostname
To view the host/machine name.
To change the hostname of your machine.
Syntax
AWS Linux Commands

39. Linux Commands AWS Linux Commands ps
To view the current running process.
ps is the shortage for Process Status. The command should be used to display the currently running processes on Unix/Linux systems
ps aux
To view the all running system processes.
ps -u user-name
To view the current running process of given user.
AWS Linux Commands

40. Linux Commands AWS Linux Commands kill Terminate a process.
Kill command in Linux is normally used to kill a suspended or hanged process.
kill -9 is used to forcefully terminate a process in Linux.
Syntax
kill process-id
AWS Linux Commands

41. Linux Commands AWS Linux Commands find
To search/find the file or directory in current or given directory .
Syntax
find /path -name file-name
(To find a particular file with in current/given directory as well as in its subdirectories)
AWS Linux Commands

42. Linux Commands AWS Linux Commands locate
To search/find the location of file-name containing the matching pattern.
Syntax
locate file-name
Options
locate -c (to count the given file)
locate -I (to search with limit)
locate -b (to search file base name)
AWS Linux Commands

43. Linux Commands AWS Linux Commands free To view the memory status.
Syntax
Options
free -l (show memory with detail)
free -m (show memory statistics in MBs)
free -g (show memory statistics in GBs)
AWS Linux Commands

44. Linux Commands AWS Linux Commands du
To view the disk used space of any file/directory.
Syntax
du directory-name
Options
du -c (show the grand total)
du -h (human readable form)
du -s (show only a total size )
AWS Linux Commands

45. Linux Commands AWS Linux Commands df To view the disk free space.
Syntax
df directory-name
Options
df -h (show detail in human readable format)
AWS Linux Commands

46. Linux Commands AWS Linux Commands su To switch an other user account
Syntax
su user-name
Options
su user-name
AWS Linux Commands

47. Linux Commands AWS Linux Commands date
To display and change the date and time.
Syntax
Options
date -s “MM/DD/YYYY hh:mm:ss”
date -s “DD month YYYY hh:mm:ss”
date -s “YYYY-MM-DD hh:mm:ss”
date -s “YYYYMMDD hh:mm:ss”
AWS Linux Commands

48. Linux Commands AWS Linux Commands Date format date +%T or +%X (Time)
date +%a or +%A (Day)
date +%D or +%F or +%x (Date)
date +%b or +%B or +%m (Month)
date +%G (Year)
AWS Linux Commands

49. Linux Commands AWS Linux Commands & To set as a background job. Ctrl+z
Syntax
Service-name &
AWS Linux Commands

50. Linux Commands AWS Linux Commands bg jobs
To view the all background running jobs.
“bg” show the total jobs.
“jobs” show the jobs in sequence.
Syntax
AWS Linux Commands

51. Linux Commands AWS Linux Commands fg
To set a background job as a foreground job.
Syntax
fg job-num
AWS Linux Commands

52. Linux Commands AWS Linux Commands Redirectors
Used to redirect data or contents to given file or new file.
Syntax
command > file-name
command >> file-name
Options
> (create new file. over write contents if exist a file)
>> (Append contents in existing file)
AWS Linux Commands

53. Linux Commands AWS Linux Commands man
A command use to view manual or help of linux commands.
Syntax
man command
man cp
q (press “q” key to exit from manual)
AWS Linux Commands

54. Linux Commands AWS Linux Commands To re-start the system. halt
To shut down the system.
poweroff
reboot
To re-start the system.
AWS Linux Commands

55. Questions & Answers Blog VaporVM 190 Route 27, L2, Edison, NJ08820
OUR
OUR WEBSITE
HANDS ON TRAINING