Basic Linux Commands for Beginners

Using a Linux machine using a shell Prompt is always a challenge these days. Many of us feel it is tougher to use Linux because of its Conventional Shell prompt, but the GUIs are so sophisticated when compared with Other Operating systems like windows, etc.

But still as a developer, one has to be good at Linux both in the GUI and as well as in Shell. For novice users and beginners, the following commands will make understand the importance of Linux and their commands.

Basic Commands

Commands	usage	Explanation
ls	ls	to list the files and folders
ls –l	ls –l	to list the files and folders in long format
chmod	chmod 777 filename	to change the mode of a file
pwd	pwd	display the present working directory
passwd	passwd	Changing the password of the current user
echo	echo “hello”	display the string hello
	echo $PATH	Display the PATH Variable stored
	echo $HOME	display the Home folder of the current user
	echo $SHELL	displays the type of shell used /bin/bash
tar	tar xf filename.tar	to decompress the tar file and extract the folders
	tar xvf filename.tar	to decompress the tar file and extract the folders with verbose mode
	tar zxvf filename.tar.gz	to decompress from gzip and the extract the tar created.
gzip	gzip –d filename.tar.gz gzip –d filename.gz	to decompress the gzip file
bzip2	bzip2 –d filename.tar.bz2 bzip2 –d filename.bz2	to decompress the bzip2 file
rm	rm name	remove a file or directory called name (the directory should be empty to be deleted)
	rm –rf name	Kill off an entire directory and all it’s includes files and subdirectories
cp	cp filename /home/hello	copy the file called filename to the folder /home/hello
mv	mv filename /home/hello	move the file called filename to the directory /home/hello
cat	cat filename	display the file called filename
su	su	login to superuser from current login (you should know the super user password)
exit	exit	exit out of the shell window or Stop being superuser and revert to normal user
dmesg	dmesg	display the boot time messages
ls	ls	list current processes
kill	kill 123	kill a specific process with ID 123
ifconfig	ifconfig	List ip addresses for all devices on the machine
rpm	rpm –ivh filename.rpm	Install the rpm package called name
	rpm –Uvh filename.rpm	Upgrade the rpm package called name
	rpm –e package	Delete the rpm package called package
	rpm –l package	List the files in the package called package
./configure	./configure	Execute the script preparing the installed files for compiling
find	find / –name fname	Starting with the root directory, look for the file called fname
	find / -name ”*fname*”	Starting with the root directory, look for the file containing the string fname

 

File Permissions

If the command ls -l is given, a long list of file names is displayed. The first column in this list details the permissions  applying to the file. If a permission is missing for a owner,
group of other, it is represented by - eg.

drwxr-x--x
Read = 4
Write = 2
Execute = 1
File permissions are altered by giving the chmod command and the appropriate octal code for each user type. eg chmod 7 6 4 filename will make the file called filename R+W+X for the owner, R+W for the group and R for others.

chmod 7 5 5 Full permission for the owner, read and execute access for the group and others.
chmod +x filename Make the file called filename executable to all users.