Linux Basic Commands

Linux Basic Commands 

By: Y.Shashidhar

Basic Linux Commands

• File Handling
• Text Processing
• System Administration
• Process Management
• Archival
• Network
• File Systems
• Advanced Commands

Sources to learn commands??

- Primary – man(manual) pages.
- man <command> shows all information about the command
- <command> help shows the available options for that command

 

File Handling commands

• mkdir – make directories Usage: mkdir [OPTION] DIRECTORY... eg. mkdir prabhat

• ls – list directory contents Usage: ls [OPTION]... [FILE]... eg. ls, ls l, ls prabhat
• cd – changes directories Usage: cd [DIRECTORY] eg. cd prabhat 

File Handling(contd...)

• pwd print name of current working directory Usage: pwd
• vim – Vi Improved, a programmers text editor Usage: vim [OPTION] [file]... eg. vim file1.txt

- cp – copy files and directories Usage: cp [OPTION]... SOURCE DEST eg. cp sample.txt sample_copy.txt cp sample_copy.txt target_dir
- mv – move (rename) files Usage: mv [OPTION]... SOURCE DEST eg. mv source.txt target_dir mv old.txt new.txt
• rm remove files or directories Usage: rm [OPTION]... FILE... eg. rm file1.txt , rm rf some_dir
• find – search for files in a directory hierarchy Usage: find [OPTION] [path] [pattern] eg. find file1.txt, find name file1.txt
• history – prints recently used commands Usage: history

Pattern

A Pattern is an expression that describes a set of strings which is used to give a concise description of a set, without having to list all elements. eg. ab*cd matches anything that starts with ab and ends with cd etc. ls *.txt – prints all text files

Text Processing

• cat – concatenate files and print on the standard output Usage: cat [OPTION] [FILE]... eg. cat file1.txt file2.txt
cat n file1.txt
• echo – display a line of text Usage: echo [OPTION] [string] ... eg. echo I love hackingterritory echo $HOME
• grep print lines matching a pattern Usage: grep [OPTION] PATTERN [FILE]... eg. grep i apple sample.txt
• wc print the number of newlines, words, and bytes in files Usage: wc [OPTION]... [FILE]... eg. wc file1.txt wc L file1.txt
• sort – sort lines of text files Usage: sort [OPTION]... [FILE]... eg. sort file1.txt sort r file1.txt

Linux File Permissions

• 3 types of file permissions – read, write, execute
• 10 bit format from 'ls l' command 1 2 3 4 5 6 7 8 9 10 file type owner group others eg. drwxrwrmeans owner has all three permissions, group has read and write, others have only read permission
• read permission – 4, write – 2, execute 1 eg. rwxrwr= 764 673 = rwrwxwx

System Administration

• chmod – change file access permissions Usage: chmod [OPTION] [MODE] [FILE] eg. chmod 744 calculate.sh
• chown – change file owner and group Usage: chown [OPTION]... OWNER[:[GROUP]] FILE... eg. chown remo myfile.txt
• su – change user ID or become superuser Usage: su [OPTION] [LOGIN] eg. su remo, su
• passwd – update a user’s authentication tokens(s) Usage: passwd [OPTION] eg. passwd
• who – show who is logged on Usage: who [OPTION] eg. who , who b , who q

Process Management

ps – report a snapshot of the current processes Usage: ps [OPTION] eg. ps, ps el
• kill – to kill a process(using signal mechanism) Usage: kill [OPTION] pid eg. kill 9 2275

Archival

• tar – to archive a file Usage: tar [OPTION] DEST SOURCE eg. tar cvf /home/archive.tar /home/original tar xvf /home/archive.tar
• zip – package and compress (archive) files Usage: zip [OPTION] DEST SOURSE eg. zip original.zip original
• unzip – list, test and extract compressed files in a ZIP archive Usage: unzip filename eg. unzip original.zip

Network

• ssh – SSH client (remote login program) “ssh is a program for logging into a remote machine and for executing commands on a remote machine” Usage: ssh [options] [user]@hostname
eg. ssh X guest@10.105.11.20
• scp – secure copy (remote file copy program) “scp copies files between hosts on a network” Usage: scp [options] [[user]@host1:file1] [[user]@host2:file2] eg. scp file1.txt guest@10.105.11.20:~/Desktop/

File Systems

• fdisk – partition manipulator eg. sudo fdisk l
• mount – mount a file system Usage: mount t type device dir eg. mount /dev/sda5 /media/target
• umount – unmount file systems Usage: umount [OPTIONS] dir | device... eg. umount /media/target

• du – estimate file space usage Usage: du [OPTION]... [FILE]...
eg. du
• df – report filesystem disk space usage Usage: df [OPTION]... [FILE]... eg. df
• quota – display disk usage and limits Usage: quota [OPTION]
eg. quota v

 

Advanced Commands

• reboot – reboot the system Usage: reboot [OPTION]
eg. reboot
• poweroff – power off the system Usage: poweroff [OPTION]
eg. poweroff

Editor commands

• kate – KDE Advanced Text Editor Usage: kate [options][file(s)] eg. kate file1.txt file2.txt
• vim – Vi Improved, a programmers text editor Usage: vim [OPTION] [file]... eg. vi hello.c
• gedit A text Editor. Used to create and edit files. Usage: gedit [OPTION] [FILE]... eg. gedit

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