The below commands are important and often used. For more checkout the image at the bottom of the article
- mkdir – make directories
Usage: mkdir [OPTION] DIRECTORY…
eg. mkdir lhn - ls – list directory contents
Usage: ls [OPTION]… [FILE]…
eg. ls, ls l, ls lhn - cd – changes directories
Usage: cd [DIRECTORY]
eg. cd lhn - pwd - print name of current working directory
Usage: pwd - vim – Vi Improved, a programmers text editor
Usage: vim [OPTION] [file]…
eg. vim lhn.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 - 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
sort r file1.txt - tar – to archive a file
Usage: tar [OPTION] DEST SOURCE
eg. tar cvf /home/archive.tar /home/original
tar xvf /home/archive.tar - kill – to kill a process(using signal mechanism)
Usage: kill [OPTION] pid
eg. kill 9 2275 - ps – report a snapshot of the current processes
Usage: ps [OPTION]
eg. ps, ps el - who – show who is logged on
Usage: who [OPTION]
eg. who , who b , who q - passwd – update a user’s authentication tokens(s)
Usage: passwd [OPTION]
eg. passwd - su – change user ID or become superuser
Usage: su [OPTION] [LOGIN]
eg. su remo, su - chown – change file owner and group
Usage: chown [OPTION]… OWNER[:[GROUP]] FILE…
eg. chown remo myfile.txt - chmod – change file access permissions
Usage: chmod [OPTION] [MODE] [FILE]
eg. chmod 744 calculate.sh - 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.zi - 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/ - 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 - reboot – reboot the system
Usage: reboot [OPTION]
eg. reboot - poweroff – power off the system
Usage: poweroff [OPTION]
eg. poweroff - 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 - bg – make a foreground process to run in background
Usage: type ‘ctrl+z’ and then ‘bg ‘ - 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
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
