Linux Commands

Basic Linux Commands

• File Handling

• Text Processing

• System Administration

• Process Management

• Archival

• Network

• File Systems

• Advanced Commands

~$ 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 name...

eg. mkdir bigdata

~$ls – list directory contents

Usage: ls [option]... [File]...

eg. ls, ls l,

ls bigdata

~$cd – changes directories

Usage: cd [directory]

eg. cd bigdata

~$ 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_path<space>dest_path

eg. cp sample.txt sample_copy.txt

cp sample_copy.txt target_dir

~$mv – move (rename) files

Usage: mv [option] source_path<space>dest_path

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.

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 India

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 [or ]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. drwxrwr means 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<space>[option] [mode]<space> [file]

eg. chmod 744 calculate.sh

~$chown – change file owner and group

Usage: chown [option]... owner[:[group]] file...

eg. chown owener_name myfile.txt

~$ su – change user ID or become superuser

Usage: su [option] [login]

eg. su owener_name, 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

~$ 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

Process Management

~$tar – to archive a file

Usage: tar [option]<space>source<space>destination

eg. tar cvf /home/archive.tar /home/original

tar xvf /home/archive.tar

~$zip – package and compress (archive) files

Usage: zip [option]<space> source<space>destination

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] [username]@hostname

eg. ssh guest@10.10.11.20

~$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 [option] 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. reboo

~$ 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

after completion of program press Esc :x to save file

~$gedit- A text Editor. Used to create and edit files.

Usage: gedit [option] [file]...

eg. gedit

~$bg – make a foreground process to run in background

Usage: type 'ctrl+z' and then 'bg <job id>'

~$ fg –to make background process as foreground process

Usage: fg [jobid]

~$ jobs – displays the names and ids of background jobs

Usage: jobs

~$sed stream

editor for filtering and transforming text

Usage: sed [option] [inputfile]...

eg. sed 's/love/hate/g' loveletter.txt

~$ awk pattern scanning and processing language

eg. awk F:'{ print $1 }' sample_awk.txt

~$find search for files in a directory hierarchy

Usage: find [option] [path] [pattern]

eg. find name file1.txt

~$locate – find or locate a file

Usage: locate [option]... file...

eg. locate file1.txt