praveenvenkatt/ex.4-linux-commands

OS EX.4-LINUX-COMMANDS

AIM:

To study and execute basic UNIX commands.

Software requirements:

Linux operating system.

COMMAND 1: ls - List Files and Directories

Syntax: 
	ls [options] [directory]
Code: 
	ls -l /home/user
Output: 
	List of files and directories in /home/user with details.

COMMAND 2: cd - Change Directory

Syntax: 
	cd [directory]
Code: 
	cd /var/www
Output: 
	Change to the /var/www directory.

COMMAND 3: pwd - Print Working Directory

Syntax: 
	pwd
Code: 
	pwd
Output: 
	/home/user (prints the current working directory).

COMMAND 4: mkdir - Create Directory

Syntax: 
	mkdir [directory]
Code: 
	mkdir my_directory
Output:	
	Creates a new directory named my_directory.

COMMAND 5: touch - Create Empty File

Syntax: 
	touch [filename]
Code: 
	touch newfile.txt
Output: 
	Creates a new empty file named newfile.txt.

COMMAND 6: cp - Copy Files and Directories

Syntax: 
	cp [options] source destination
Code: 
	cp file.txt /backup/
Output: 
	Copies file.txt to the /backup/ directory.

COMMAND 7: mv - Move/Rename Files and Directories

Syntax: 
	mv [options] source destination
Code: 
	mv oldfile.txt newfile.txt
Output: 
	Renames oldfile.txt to newfile.txt.

COMMAND 8: rm - Remove Files and Directories

Syntax: 
	rm [options] [file/directory]
Code: 
	rm file.txt
Output: 
	Deletes file.txt.

COMMAND 9: cat - Concatenate and Display File Content

Syntax: 
	cat [filename]
Code: 
	cat file.txt
Output: 
	Displays the content of file.txt.

COMMAND 10: more - View File Content Page by Page

Syntax: 
	more [filename]
Code: 
	more longfile.txt
Output: 
	Allows you to view the content of longfile.txt one page at a time.

COMMAND 11: less - View File Content with Navigation

Syntax: 
	less [filename]
Code: 
	less largefile.txt
Output: 
	Displays largefile.txt with navigation capabilities.

COMMAND 12: head - Display Top Lines of a File

Syntax: 
	head [options] [filename]
Code: 
	head -n 5 file.txt
Output: 
	Shows the first 5 lines of file.txt.

COMMAND 13: tail - Display Bottom Lines of a File

Syntax: 
	tail [options] [filename]
Code: 
	tail -n 10 file.log
Output: 
	Shows the last 10 lines of file.log.

COMMAND 14: grep - Search Text in Files

Syntax: 
	grep [options] 'pattern' [file(s)]
Code: 
	grep 'keyword' file.txt
Output: 
	Lists lines containing 'keyword' in file.txt.

COMMAND 15: find - Search for Files and Directories

Syntax:
	find [path] [expression]
Code: 
	find /home/user -name '*.txt'
Output: 
	Finds all .txt files under /home/user.

COMMAND 16: chmod - Change File Permissions

Syntax: 
	chmod [options] permissions file(s)
Code: 
	chmod 644 file.txt
Output: 
	Sets read and write permissions for the owner and read-only permissions for others on file.txt.

COMMAND 17: chown - Change File Ownership

Syntax: 
	chown [options] user:group file(s)
Code: 
	chown user:group file.txt
Output: 
	Changes the owner and group of file.txt.

COMMAND 18: tar - Archive and Compress Files

Syntax: 
	tar [options] [file(s)]
Code: 
	tar -cvzf archive.tar.gz dir/
Output: 
	Creates a compressed archive of the dir/ directory.

COMMAND 19: df - Display Disk Space Usage

Syntax: 
	df [options] [filesystem(s)]
Code: 
	df -h
Output: 
	Shows disk space usage in a human-readable format.

COMMAND 20: du - Display Directory Space Usage

Syntax: 
	du [options] [directory]
Code: 
	du -sh /var
Output: 
	Displays the total size of the /var directory in a human-readable format.

COMMAND 21: ps - Display Process Status

Syntax: 
	ps [options]
Code: 
	ps aux
Output: 
	Lists running processes with details.

COMMAND 22: kill - Terminate Processes

Syntax: 
	kill [signal] [PID]
Code: 
	kill -9 1234
Output: 
	Sends a SIGKILL signal to process with PID 1234.

COMMAND 23: ssh - Secure Shell

Syntax: 
	ssh [user@]hostname
Code: 
	ssh user@remote-server
Output: 
	Establishes a secure remote connection to remote-server.

COMMAND 24: scp - Securely Copy Files Over SSH

Syntax:
	scp [options] source destination
Code: 
	scp file.txt user@remote-server:/path/
Output: 
	Copies file.txt to a remote server over SSH.

COMMAND 25: wget - Download Files from the Internet

Syntax: 
	wget [options] [URL]
Code: 
	wget https://example.com/file.zip
Output: 
	Downloads file.zip from the specified URL.

RESULT:

Thus basic UNIX commands are studied and executed.