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Cheat sheet for linux



mkdir – make directories
Usage: mkdir [OPTION] DIRECTORY…
eg. mkdir lhnls – list directory contents
Usage: ls [OPTION]… [FILE]…
eg. ls, ls ­l, ls lhncd – changes directories
Usage: cd [DIRECTORY]
eg. cd lhnpwd ­-  print name of current working directory
Usage: pwdvim – Vi Improved, a programmers text editor
Usage: vim [OPTION] [file]…
eg. vim lhn.txtcp – copy files and directories
Usage: cp [OPTION]… SOURCE DEST
eg. cp sample.txt sample_copy.txt
cp sample_copy.txt target_dirmv – move (rename) files
Usage: mv [OPTION]… SOURCE DEST
eg. mv source.txt target_dir
mv old.txt new.txtrm ­ remove files or directories
Usage: rm [OPTION]… FILE…
eg. rm file1.txt , rm ­rf some_dirfind – search for files in a directory hierarchy
Usage: find [OPTION] [path] [pattern]
eg. find file1.txt, find ­name file1.txthistory – prints recently used commands
Usage: historycat – concatenate files and print on the standard output
Usage: cat [OPTION] [FILE]…
eg. cat file1.txt file2.txt
cat ­n file1.txtecho – display a line of text
Usage: echo [OPTION] [string] …
eg. echo I love India
echo $HOMEgrep ­- 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.txtsort – sort lines of text files
Usage: sort [OPTION]… [FILE]…
eg. sort file1.txt
sort ­r file1.txttar – to archive a file
Usage: tar [OPTION] DEST SOURCE
eg. tar ­cvf /home/archive.tar /home/original
tar ­xvf /home/archive.tarkill – to kill a process(using signal mechanism)
Usage: kill [OPTION] pid
eg. kill ­9 2275ps – report a snapshot of the current processes
Usage: ps [OPTION]
eg. ps,  ps ­elwho – show who is logged on
Usage: who [OPTION]
eg. who , who ­b , who ­qpasswd – 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, suchown – change file owner and group
Usage: chown [OPTION]… OWNER[:[GROUP]] FILE…
eg. chown remo myfile.txtchmod – change file access permissions
Usage: chmod [OPTION] [MODE] [FILE]
eg. chmod 744 calculate.shzip – package and compress (archive) files
Usage: zip [OPTION] DEST SOURSE
eg. zip original.zip originalunzip – list, test and extract compressed files in a ZIP archive
Usage: unzip filename
eg. unzip original.zissh – 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@10.105.11.20scp – 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 ­lmount – mount a file system
Usage: mount ­t type device dir
eg. mount /dev/sda5 /media/targetumount – unmount file systems
Usage: umount [OPTIONS] dir | device…
eg.  umount /media/targetdu – estimate file space usage
Usage:  du [OPTION]… [FILE]…
eg. dudf – report filesystem disk space usage
Usage: df [OPTION]… [FILE]…
eg. dfquota – display disk usage and limits
Usage: quota [OPTION]
eg. quota ­vreboot – reboot the system
Usage: reboot [OPTION]
eg. rebootpoweroff – power off the system
Usage: poweroff [OPTION]
eg. poweroffkate – KDE Advanced Text Editor
Usage:  kate [options][file(s)]
eg. kate file1.txt file2.txtvim – Vi Improved, a programmers text editor
Usage: vim [OPTION] [file]…
eg. vi hello.cgedit ­ A text Editor. Used to create and edit files.
Usage: gedit [OPTION] [FILE]…
eg. geditbg – 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: jobssed ­  stream editor for filtering and transforming text
Usage: sed [OPTION] [input­file]…
eg. sed ‘s/love/hate/g’ loveletter.txtawk ­ pattern scanning and processing language
eg.  awk ­F: ‘{ print $1 }’ sample_awk.txtfind ­ search for files in a directory hierarchy
Usage: find [OPTION] [path] [pattern]
eg. find ­name file1.txtlocate – find or locate a file
Usage: locate [OPTION]… FILE…
eg. locate file1.txt

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Linux File Permissions

3 types of file permissions – read, write, execute10 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
permissionread permission – 4, write – 2, execute ­1
eg. rwxrw­r­­   = 764
673    =   rw­rwx­wx

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