group by 13

1. PSG COLLEGE OF TECHNOLOGY
20MX15 - UNIX ARCHITECTURE AND PROGRAMMING
By
21MX124 - Sandhiya M.
21MX207 - Karpaga Prasanth K.
21MX210 - Maheash Kumar M.
21MX213 - Om Raju V.
Ms. A. Kalyani
Asst.Professor MCA (PSG)

2. The ‘cd’ Command
The ‘cd’ Command is used to change the current
directory to another directory.
Syntax: cd [directory path]

3. The ‘bc’ Command
• bc command is used for command line calculator. It is similar to basic calculator
by using which we can do basic mathematical calculations.
Arithmetic operations are the most basic in any kind of programming language.
Linux or Unix operating system provides the bc command and expr
command for doing arithmetic calculations. You can use these commands in bash
or shell script also for evaluating arithmetic expressions.
Syntax:
Bs [-hlwsqv] [more options] [file…]

4. bc - Supports
• Arithmetic operators.
• Increment or Decrement operators.
• Assignment operators.
• Comparison or Relational operators.
• Logical or Boolean operators.
• Math functions.
• Conditional statements.
• Iterative statements.

5. The ‘man’ Command
• Man command in Linux is used to display the user manual of any command that we
can run on the terminal. provides a detailed view of the command which
includes NAME, SYNOPSIS, DESCRIPTION, OPTIONS, EXIT STATUS,
RETURN VALUES, ERRORS, FILES, VERSIONS, EXAMPLES,
AUTHORS and SEE ALSO.
Syntax:
$man [options] [command name]

7. The ‘who’ Command
• The Linux "who" command lets you display
the users currently logged in to your UNIX or
Linux operating system. Whenever a user
needs to know about how many users are using
or are logged-in into a particular Linux-based
operating system, he/she can use the "who"
command to get that information.

8. The ‘whoami’
Command
• It displays the username of the current user
when this command is invoked.
• Displays user, group and privileges
information for the user who is currently
logged on to the local system. If used without
parameters, whoami displays the current domain
and user name.

9. The ‘pwd’ Command
• pwd stands for Print Working Directory. It prints the path of the working directory,
starting from the root. pwd is shell built-in command(pwd).
• Options:
pwd -l : Prints the symbolic path.
pwd –p : Prints the Actual path.

10. The ‘mkdir’ Command
• Mkdir stands for make directory .
• The “mkdir” command is used to create a directory.
• -p: option create a hierarchy of directories.
Syntax: mkdir [directory path]
ubuntu@ubuntu-VirtualBox:~$ mkdir folder
ubuntu@ubuntu-VirtualBox:~$ mkdir folder1
ubuntu@ubuntu-VirtualBox:~$ mkdir -p folder1/subfolder/anotherfolder

11. The ‘rmdir’
Command
Rmdir stands for remove directory.
The “rmdir” command is used to remove
directory.
• Syntax: rmdir [directory path]
• ubuntu@ubuntu-VirtualBox:~$ rmdir folder

12. The ‘ls’
Command
The Linux ls command allows you to view a
list of the files and folders in a given
directory. You can also use this command to
display details of a file, such as the owner of
the file and the permissions assigned to the
file.
• ubuntu@ubuntu-VirtualBox:~$ ls
• 21mx124_practice_commands Documents Music
samplefile Videos
• 21mx124_practice_commands_2 Downloads Pictures
samplefile1
• Desktop folder1 Public Templates

13. THE ‘LS’
COMMAND
OPTIONS

20. The ‘Touch’
Command
The touch command is a standard command used in
UNIX/Linux operating system which is used to create,
change and modify timestamps of a file.
• Syntax: Touch [File_name]
• ubuntu@ubuntu-VirtualBox:~$ touch samplefile
• ubuntu@ubuntu-VirtualBox:~$ touch samplefile1
• ubuntu@ubuntu-VirtualBox:~$ ls
• 21mx124_practice_commands Documents Music samplefile
Videos
• 21mx124_practice_commands_2 Downloads Pictures
samplefile1
• Desktop folder1 Public Templates

21. The ‘mv’ Command
mv stands for move. mv is used to move one
or more files or directories from one place to
another in a file system like UNIX. It has two
distinct functions.
• It renames a file or folder.
• It moves a group of files to a different
directory.

22. The ‘date’ Command
• Date command is used to display the system date and time. It is also used
to set date and time of the system.
• By default the date command displays the date in the time zone on which
unix operating system is configured.
• You must be the super-user to change the date and time.
Syntax:
$date

23. The ‘cat’ Command
Cat command stands for concatenate. It reads data from the file and gives their
content as output. It helps us to create, view, and concatenate files.
Frequently used cat commands:
• To view a single file .
Command:
$cat filename
• To view multiple files
Command:
$cat file1 file2

24. • Create a file
Command:
$ cat >newfile
• Copy the contents of one file to another file.
Command:
$cat [filename-whose-contents-is-to-be-copied] > [destination-filename]

25. The ‘More’ Command
• more command is used to view the text files in the command prompt, displaying
one screen at a time in case the file is large.
• The more command also allows the user do scroll up and down through the page.
• When the output is large, we can use more command to see output one by one.
• Another application of more is to use it with some other command after a pipe.

26. Syntax:
The syntax along with options and command is as follows.
more [-options] [-num] [+/pattern] [+linenum] [file_name]
[-options]: any option that you want to use in order to change the way the file is
displayed.
(-d, -l, -f, -p, -c, -s, -u)
[-num]: type the number of lines that you want to display.
[+/pattern]: replace the pattern with any string that you want to find in the text file.
[+linenum]: use the line number from where you want to start displaying the text
content.
[file_name]: name of the file containing the text that you want to display on the
screen.

27. The ‘less’ Command
• Less command is used to read the contents of a file one page at a time.
• It has faster access because if file is large it doesn’t access the complete file, but
accesses it page by page.
• For example, if it’s a large file and you are reading it using any text editor, then
the complete file will be loaded to main memory. The less command doesn’t load
the entire file, but loads it part by part which makes it faster.
Syntax :
less filename

28. The ‘print’ Command
• printf command is used to display the given string, number or any other format specifier on the
terminal.
• It works the same way as “printf” works in programming languages like C.
Syntax:
$printf [-v var] format [arguments]
The most commonly used printf specifiers are %s, %b, %d, %x and %f.
1) %s : It is basically a string specifier for string output. $printf "%sn" "Hello, World!"
2) %b : It is same as string specifier but it allows us to interpret escape sequences with an argument.
printf "%sn" "Hello, World! n" "From Geeks For Geeksn"
3) %d specifier: It is an integer specifier for showing the integral values.

30. The ‘echo’ Command
• echo command in linux is used to display line of text/string that are passed as an
argument . This is a built in command that is mostly used in shell scripts and
batch files to output status text to the screen or a file.
Syntax:
Echo [option] [string]

31. The ‘lp’ Command
• The lp command in Linux stands for 'Line printer' which lets you print the files
through the terminal. There is no need to change or manage the settings through
the GUI. You can simply manage the printers using lp command. This command
is also known as the printer management command Linux.
• This command is also known as the printer management command Linux. The lp
command in Linux is one of the CUPS i.e. Common Unix Printing System.
Syntax:
lp [filename]

32. Options of lp command
• d: to print the file using a particular printer.
• -n: print multiple copies of the document.
• -q: Set the priority of the printer in the printer queue.
• -t: to assign a name to the job.
• -o: assigns one or more job.
• -i: specifies an existing job to modify.
• -m: notifies the recipient when the job is completed.
• -h: denotes the hostname of the server.
• -E: forces the encryption while connecting to the server.

33. The ‘rm’Command
• The 'rm' means remove. This command is used to remove a file. The command
line doesn't have a recycle bin or trash unlike other GUI's to recover the files.
Hence, be very much careful while using this command. Once you have deleted a
file, it is removed permanently.
• Syntax:
rm <filename>
• Example:
rm myfile1

34. Options in rm
• rm *extension - Used to delete files having same extension.
• rm -r or R - To delete a directory recursively.
• rm –i - Remove a file interactively.
• rm –rf - Remove a directory forcefully.

35. The ‘cp’
Command
• cp stands for copy. This
command is used to copy files or
group of files or directory. It
creates an exact image of a file on
a disk with different file
name. cp command require at
least two filenames in its
arguments.
Syntax: cp [Source file]
[destination file]

36. cp –R : If the command contains two directory names, cp copies all files of the source
directory to the destination directory, creating any files or directories needed. This mode of
operation requires an additional option, typically R, to indicate the recursive copying of
directories.
• Syntax: cp -R [Src_dir] [des_dir]
cp -i : i stands for Interactive copying. With this option system first warns the user before
overwriting the destination file. cp prompts for a response, if you press y then it overwrites
the file and with any other option leave it uncopied.
• Synatx: cp –I [Src_file] [des_file]