For the past 11 days, we are playing with Linux and git. Now, it's time to revise and keep them all in one place. Here we go...

Topic's blog will be long but it covers all the essential commands in Linux and Git

All essential Linux commands

commands	Operations & Examples
a2p	translate awk to Perl
e.g. a2p myfile.awk>myfile.pl(translate myfile.awk into pl file)
alias	create another name for a command
alias p="pwd"
(set p as alias for pwd)
apropos	view the searched item in man pages
e.g. apropos find
(list entries with "find" on the man page)
apropos -e	view searched items in man pages
e.g. apropos -e nice
(-e: show the exact word in man pages)
apt-get	install, remove or update a package
e.g. apt-get install libc6
(install libc6 package)
aspell	check and correct for misspellings
aspell -c test.txt
(-c check spelling in test.txt file)
at	run a job at a scheduled time
at 1 AM fri
(run the job at 1 am friday)
awk	match text by regular expression
e.g. awk 'length($0)>88'text.txt
(list only lines longer than 88 words)
basename	display the last part of a file path
e.g. basename homefoousrfile.txt
(output:file.txt)
bc	perform calculations by a calculator
e.g. bc 8+9
(output: 17)
bg	resume a stopped job in the background
e.g. bg %3
(resume %3 job in the background)
bunzip2	uncompress a file from the zip format
e.g.bunzip2 myfile.tar.bz2
(uncompress myfile.tar.bz2)
bzip2	compress a file to zip format
e.g.bzip2 myfile.dat
(compress myfile.dat)
cal	display a month or year calendar
e.g. cal 2022
(display 2022 calendar)
cal -3	display a month or year calendar
e.g. cal -3
(-3 display 3 months)
cat	display contents of one or more files
cat -n myfile.txt
(-n specify the number of output lines)
cd	change directory
cd homeuser/mydir
(change the current directory to mydir)
chattr	set attributes for a file
e.g. chattr +i myfile.txt
(+i make the file read-only)
chfn	change the user's finger information
e.g. chfn
(change all user's information)
chfn -f	change the user's finger information
e.g. chfn -f full-name
(-f: change full name)
chgrp*	change the group ownership
e.g. chgrp groupname usrmyfile.txt
(alter group ownership of myfile.txt)
chkconfig*	View and modify run-level file
e.g. chkconfig -list
(-list: list services of run level)
chmod	change access permission
e.g. chmod 755 filename
(set file access permission as 755)
chown*	the command used by the root user
chpasswd*	change password for users
e.g. chpasswd
(then enter username:password)
chsh*	change the login shell for user
e.g. chsh -s binbash ray
(-s specify login shell)
cksum	produce a CRC checksum number
e.g. cksum file.txt
output checksum number of file.txt)
clear	clear the screen
e.g. clear
clear the shell window
cmp	compare two files text byte by byte
e.g. cmp first.txt second.txt
(compare first.txt and second.txt)
collectl	monitor the current system status
e.g. collectl
(list cpu, sys, inter .etc information)
comm	compare two files text line by line
e.g. comm first.txt second.txt
(compare first.txt second.txt)
cp	copy file(s) to another directory
cp myfile.txt/mydir
(copy myfile.txt to mydir)
cp -p	copy file(s) to another directory
cp -p myfile.txt/mydir(-p: keep original permission)
cp -a	copy file(s) to another directory
e.g. cp -a myfile.txt/mydir
(-a: keep original attributes)
cpio -o	output archived cpio file
e.g. cpio -o>directory.cpio(-o:backup to an archive cpio file)
cpio -i	input archived cpio file
cpio -i<directory.cpio
(-i restore it from an archive cpio file)
crontab	create a job to run at the specified time
e.g. crontab
(set to run jobs at regular intervals.)
crontab -e	run a recurring job at a specified time
e.g. crontab -e (-e allow edit the crontab file)
crontab -l	run a recurring job at a specified time
e.g. crontab -l
(-l: lists the crontab files)
crontab -r	run a recurring job at a specified time
e.g. crontab -r
(-r remove the crontab files)
csplit	split a file into some separate files
e.g. csplit myfile.txt "/part1/""part2"
(separate files named xx00,xx01)
cut -d	show the specified field of a file
e.g. cut -d ":" myfile.txt
(-d : specify a field delimeter":"
cut -c	extract contents from a file
e.g. cut -c6 myfile.txt
cut -f	extract contents from a file
e.g. cut -fe myfile.txt
(-f3 -- specify a field number as 3)
date	show the date and time
e.g. date
(display the current date and time)
date -s	set the date and time
e.g. date -s "11/20/2014"
-s --set the date)
dc	open a command line desk calculator
e.g. dc
"dc" means desk calculator
dd	data dump to convert and copy a file
e.g. dd if=devsda of=devsdb(copy data from sda to sdb)
dmesg	printout all kernel log messages
e.g.dmesg>kmsg.txt
(output kernel message to kmsg.txt)
df	display free disk space
e.g. df
(display the file system free space)
df -m	display free disk space
e.g. df -m
(-m:display size in Mb)
dhclient	configure network interfaces
dhclient etho
(renew IP address of etho)
diff	show the difference between the two files
e.g. diff firstfile.txt secondfile.txt
(display difference above two files)
diff3	show differences among the three files
e.g. diff3 file1.txt file2.txt file3.txt
(display difference above three files)
dig	display the details of DNS servers
e.g. dig vxaxx.com
(list information about xvxaxx.com)
dir	show directory contents
e.g. dir
(display current directory contents)
dircolors	show color settings for "ls" command
dircolors
(display directory coloring of ls)
dirname	remove the last part of a file path
e.g. dirname foobar/baz/myfile.txt
(output:foobar/baz)
du -s	display disk usage
e.g. du -s .
(-s list files size in current directory)
du -h	display disk usage
e.g. du -h myfile.txt
(-h: show human readable units)
dump -f	makes a backup of a filesystem
e.g. dump -f0 filebk/mydir
(-f:backup -0:dumplevel filebk:dump-file)
echo	display input on standard output
e.g. echo "Hello, world"
show "Hello, world"
echo -e	display text using an escape sequence
e.g. echo -e "\n Hello, world"
(-e:allow use \n to show text)
ed	open a command-line text editor
e.g. ed myfile.txt
(open myfile.txt with text editor)
egrep	Search file(s) for a specified regex
e.g. egrep "new
eject	eject the cd or DVD tray
eject cdrom
(eject cdrom tray)
eject -t	eject or close the cd or DVD tray
e.g. eject -t cdrom
(-t:close an open cdrom tray)
emacs	powerful, extensible file editor
e.g. emacs file.txt
(launch emacs and open file.txt)
env	the show set the environmental variables
e.g. env
(list current environment variable)
eval	make a command from its arguments
e.g. UPLS="eval cd..;ls"
(create a command named UPLS)
exit	exit the shell
exit
(terminate the program and logout)
expand	convert tabs into spaces
e.g. expand myfile.txt
(convert tabs to spaces for myfile.txt)
expand -t	convert tabs into spaces
e.g. expand -t 3 myfile.txt
(-t: set tabs 3 characters apart)
export	set an environmental variable & value
e.g. export newvar=8 echo $newvar
(output:8)
expr	evaluate an expression
expr 10+8
(output: 18)
factor	show the prime factors of a number
factor 1001
(output: 7 11 130
fc	list,edit, and re-execute last commands
e.g. fc -l
(-l: list the history of commands)
fdisk*	manipulate the hard disk partitions
e.g. fdisk devhdb
(list harddisk partitions information)
fg	resume a stopped job in the foreground
fg %3
(resume the job 3 in foreground)
fgrep	Search file(s) for a specified string
e.g. fgrep "good" myfile.txt
(search myfile.txt for "good")
file	detect the file type
e.g. file file1.txt
(determine file type of file1.txt)
find -print -name	find file(s) in a directory named dir
e.g. find dir -print -name 'abc.txt'
(-print:print -name:specify file name)
finger	show the user's information
e.g. finger username
(list the user's login name, time etc.)
fmt	format text files
e.g. fmt myfile1.txt>myfile2.txt
(format myfile1.txt & output to myfile2)
fmt -u	format text files
fmt -u myfile.txt
(-u: provide uniform word spacing)
fold	wrap each line to fit a specified width
e.g. fold -w 15 myfile.txt
(-w specify how many words)
for in	set conditional parameter for loop
e.g. for n in 3 6 9 do echo $n done
(output:3 6 9)
free	displays free memory information
e.g free
(list free, used,total memory..)
free -m	displays free memory information
e.g. free -m
(-m: show sizes in Mb)
fsck*	file system check
e.g. fsck
(check or fix linux file system)
ftp	transfer files by file system transfer protocol
e.g. ftp serverURL
(transfer files using ftp)
gawk	find or replace text in a file
e.g. gawk 'length($0)>88'
(list lines longer than 88 characters)
grep	match a specified string or regex.
e.g. grep onestring myfile.txt
(search myfile.txt for onestring)
groups	list groups to which the user belongs
e.g. groups
(print the groups of user)
groupadd*	add a new group
e.g. groupadd newgroup
(create new group)
groupadd* -f	add a new group
e.g. groupadd -f newgroup
(-f:check group doesn't exit)
groupdel*	delete an existing group
e.g. groupdel existinggroup
(remove an existing group)
groupmod* -n	modify an existing group
e.g. groupmod -n newgrp oldgrp
(-n change group name)
gunzip	uncompress a file from gzip format
e.g. gunzip myfile.txt.gz
(uncompress myfile.txt.gz)
gzip	compress a file to gzip format
e.g. gzip myfile.txt
(compress myfile.txt)
halt	shutdown the system
e.g. halt
(power off the system)
hash	access the hash table
e.g. hash(list commands from hash table)
head	display some frontlines in a file
e.g. head myfile.txt
(output the first ten lines of myfile.txt)
head -n	display some front lines in a file
e.g. head -n 4 myfile.txt
(output the first 10 lines of myfile.txt)
help	show help information on commands
e.g. help echo
(show information about echo)
history	show the commands history
e.g. history
(list commands in this shell session)
host	find IP address of a domain name
e.g. host websprogram.com
(show ip of webprogram.com)
hostid	display the id of the current host in hex.
e.g. hostid
(print the current host id)
hostname	show or set the hostname
e.g. hostname
(display the name of current host)
id	show the user or group id number
e.g. hostname
(display the root user uid,gid,e.t.c)
ifconfig	show, and configure the network interface
e.g. ifconfig
(display the network settings)
init*	set the system run level
e.g. init 5
(change to runlevel 5)
info	show help information of a command
e.g. info man
(show help page for man)
install	copy files,set permission, ownership
e.g. install myfiles homeuser(copy myfiles to user directory)
install -o	copy files, set permission, ownership
e.g. install -o myfiles.ray/home
(-o:specify ownership)
jobs	show all jobs status
e.g. jobs
(list all running jobs information)
join	join lines of files having a common field
e.g. join myfile.txt myfile2.txt
(join lines of two files by same field)
join	join lines of two files
e.g. join -i myfile1.txt myfile2.txt
(-i:ignore the difference)
kill	stop a job by the number
e.g. kill %3
(terminate job %3)
kill	stop a process by PID
e.g. kill 3965
(terminate process 3965)
killall	stop a process by name
e.g. killall no respond
(terminate process no respond)
last	show most recently logged-in users
e.g. last
(list recent user's date,time...)
lastb	show bad login attempts
e.g. lastb
(display bad login attempts)
lastlog	display the last login information
e.g. lastlog -u username
-u:specify user
less	show contents page by page
e.g. less myfile.txt
(display myfile.txt page by page)
let	petform arithmatic on shell variables
e.g. let a =12;let a=a+8;
echo $a
(output: 20)
link	create a link to a file
link file1.txt file2.txt
(create a link from file1 to file2)
ln	create a hard link to a file
e.g.~/myfile.txt
(create a hard link to myfile.txt)
ln -s	create a link between two files
e.g. ln -s file1.txt file2.txt
(create a symbolic link to file1/file2)
locate	find the location of a file or a directory
e.g. locate myfile.txt
(locate myfile.txt on the local machine)
logname	show the current user's login name
e.g. logname
(display the login name of user)
look	show words matching a given prefix
e.g. look ab
(output:aba,abb,abc,abd,...)
lpc	run the line printer control program
e.g. lpc status
(show status of the current print queue)
lpq	show the print queue status
e.g. lpq
(list the print queue)
lpr	send a print request to a printer
lpr myfile.txt
(send myfile.txt to printer)
lprm	cancel the printing job in the print queue
lprm 2
(remove printing job 2)
ls	list the contents of the current directory
e.g. ls
(list files and sub-directories)
ls -l	long list contents of the current directory
e.g. ls -l
(-l: long lists including permissions)
ls -a	lists all entries including hidden files
e.g. ls -a
(-a: show all files)
ls -t	lists all entries by time stamps
e.g. ls -t
(-t: show by time stamps)
ls -lh	lists contents in the current directory
e.g. ls -lh
(-LH: list files with size in mb and gb)
lsattr	list attributes of a file or a directory
e.g. lsattr myfile.txt
(show myfile.txt attribute)
lsof	list opened files
lsof
(list all opened files)
man	get command help from manual
e.g. man cat
(show manual page for cat)
man -k	search manual pages for keyword
e.g. man -k printf
(-k: specify a keyword)
md5sum	create a md5 checksum number
e.g. md5sum -c file.txt
(-c:validate file against a checksum)
mesg	enable or disable messaging
e.g. mesg
(show the current write status)
mesg y/n	enable or disable messaging
e.g. mesg y/n
(y or n: permit or deny messaging)
mail	send and receive mails
e.g. mail ray@charan.com
(email to ray@charan.com)
mkdir	make a new directory
e.g. mkdir mydir
(create a directory named mydir)
mknod	make a device file
e.g. mknod devdk b 45 0
(dk:device; b:block;45:major no.;0:minorno.)
more	show content one screen at one time
e.g. more +2 myfile.txt
(+2 ;begining at line 2)
mount	mount a storage device
e.g. mount devcd
(mound a device cd)
mount -l	mount or show devices
e.g. mount -l
(-l: list all mounted devices)
mt	magnetic tape drive control
e.g. mt -f devtape eod (-f select eod;move to end of data)
mv	move a file to another directory
e.g mv myfile.txt homeuser/mydir
(move myfile.txt to mydir directory)
mv	rename a file
e.g. mv myfile1.txt myfile2.txt
(rename myfile1 to myfile2)
netstat	display network status
e.g. netstat
(print network connections,routing tables,etc)
nice*	set the priority level of a job
e.g. nice -19 ftp
(set prioriy level as 19 for ftp)
nl	add text with number lines
e.g. nl mylist.txt
(make number lines for mylist.txt)
nohup	ignore hangup signals
e.g. nohup find ftp
(run ftp ignoring hangup signals)
nslookup	query internet name servers for IP
e.g.nslookup myxxexample.com
(return Ip like 75.245.246.xxx)
passwd	modify a user password
e.g. passwod username
(change password for username)
paste	merge lines of multiple files
e.g. paste file1.txt file2.txt
(merge contents for file1 and file2)
pidof	show processId of the running program
e.g. pidof console
(display console's process id)
ping	send data to a host, await a response
e.g. ping vxmijfz.com
(test if remote host can be reached)
ping -c	test if the remote host can be reached
e.g. ping -c5 xvxmijfz.com
(-c5:specify the number of pings)
pkill	kill a running process
e.g. pkill firefox
(stop web browser firefox)
pr	prepare text files for printing
e.g. pr myfile.txt
(prepare myfile.txt for printing)
pr -n	prepare text files for printing
e.g. pr -n myfile.txt
(-n:specify number in each line)
pr -h	prepare text files for printing
e.g. pr -h "good" myfile.txt
(-h: specify a header)
printenv	show the environmental variables
printenv
(list values of environment variables)
printf	format and print data
e.g. printf "start\b"
(-b:backspace output:start)
printf	format and print data
e.g. printf 'hello \n world \n !'
(\n:prints by newlines. output 3 lines)
ps -f	show the process status
e.g. ps -f
(-f : full information of current process)
ps -u	show the process status
e.g. ps -u ray
(-u:specify a user's current process)
pstree	display process in a tree structure
e.g. pstree
(show all process as a tree)
pwd	print working directory
e.g. pwd
(display current directory)
rcp	remotely copy files between two hosts
e.g. rcp file.txt host2:/dir2/file.txt
(remotely copy file.txt to host2)
read	read a line from the standard input
e.g. read name(input ray) echo "$name"(output ray)
reboot*	restart the system
e.g. reboot
(cause the computer to restart)
renice*	change the priority level of a job
e.g. renice 3 23001
(set priority level as 3 for job23001)
restore	restores data from the backup file
e.g. restore -f databackup
(-f:specify a backup file)
rlogin	remotely log in to a system
e.g. rlogin -l username domain.com
(-l: specify a username)
rm	remove one or more files
e.g. rm myfile.txt
(remove myfile.txt)
rm -r	remove non-empty directory
e.g. rm -r /NonEmptyDir
(-r: remove directory and itscontent)
rm -i	remove a non-empty directory or a file
e.g. rm -i myfile.txt
(-i: ask before removing)
rmdir	remove empty directory
e.g. rmdir /emptydir
(delete directory without contents)
route	show or modify the IP routing table
e.g. route -n
(-n: show in numerical format)
rsync	remotely synchronize files
e.g. rsync myfile host2:/dir2/myfile
(sync. myfile with remote host2)
scp	securely copy files between two hosts
e.g. scp file.txt host2:/dir2/file.txt
(securely copy file to remote host2)
screen	open the terminal window manager
e.g. screen
(start a new screen)
sdiff	show two files’ different side by side
e.g. sdiff myfile1.txtmyfile2.txt
(compare two files sideby side)
sed	filter and transform input text
e.g. sed “{print $3}” myfile.txt
(display the third word of each line)
seq	list sequent numbers in a given range
e.g. seq 1 8(output: 1 2 3 4 5 6 7 8)
seq -w	list sequent numbers in a given range
e.g. seq –w 1 3
(-w: with zeros output: 01 02 03 )
seq	list sequent numbers in a given range
e.g. seq –s	1 3
(-s: with separators output: 1
set	set shell variable or function
e.g. set n=`who am i`; echo $n
(output: who am i)
sftp	securely transfer files by FTP
e.g. sftp SeverURL
(securely transfer files to a Server)
shopt	show the shell option settings
e.g. shopt
(show the shell behavior settings)
shutdown *	close system
e.g. shutdown 22:00
(shut down at 22:00 o’clock)
shutdown-h close system
e.g. shutdown –h +5
(-h+5: halt after 5 minutes)
shutdown -r	shutdown and restart
e.g. shutdown -r now
(-r:shut down and instantly restart)
sleep	pause for a specified amount of time
e.g. sleep 10
(pause for 10 seconds)
sort	show sorted contents alphabetically
e.g. sort -r myfile.txt
(-r sort file in reverse order)
split -b	split a file to some files in a given size
e.g. split -b 11 file.txt
(split file to
some 11 byte files named
xaa,xab,xac, etc.)
split -l	split a file to some files in a given size
e.g. split -l 8 file.txt
(split file to
some 8 line files named
xaa,xab,xac, etc.)
ssh	login to remote secure shell
e.g. ssh ray@myexample.com
(securely connect to a remote host)
ssh -l	login to remote secure shell
e.g. ssh -l username hostname
(-l
specify your remote username)
stat	list status about file size, access, etc.
e.g. stat myfile.txt
(show myfile.txt statistics)
su	switch user
e.g. su user2
(switch user named user2)
su -l	login as a root super user
e.g. su –l
(-l:enter password, login root
account )
sudo -u	execute a command as another user
e.g. sudo -u user2 ls homemydir
(-u:
specify user2 to execute ls cmd)
sudo -v	refresh the authentication timeout
e.g. sudo -v
(next sudo will not require
password.)
sudo -k	expire the authentication timeout
e.g. sudo -k
(next sudo will require password.)
sum	summarize a file with a checksum
e.g. sum myfile.txt
(create a
checksum for myfile.txt)
suspend	suspend the working shell
e.g. suspend
(pause system during execution)
sync	synchronize disk data with memory
e.g. sync
(flush all file system buffers to disk)
tac	display lines of a file in reverse
order
e.g. tac myfile.txt
(print file from last line to first line)
tail	show the final part of a file
e.g. tail -n 20 file.txt
(-n20:output last 20 lines of file.txt)
talk	communicate with another user
e.g. talk ray
(talk to user ray)
tar -xf	extract an archived tar file
e.g. tar -xf archive.tar
(-xf: extract an archive tar file)
tar -cf	create an archived tar file
e.g. tar -cf archive.tar
(-cf: create an archive tar file)
tee	print standard output, write to a file
e.g. sort file1.txt	tee file2.txt
(sort
file1.txt and write to file2.txt)
tee -a	print standard output, write to a file
e.g. sort file1.txt	tee –a file2.txt
(-a:
append instead of overwrite)
test	calculate a boolean expression
e.g. [ 8 -gt 6 ]; echo $?
(output: 0 0:true; 1:false)
test	calculate a boolean expression
e.g. [ 5 -eq 6 ]; echo $?
(output: 1 0:true; 1:false)
time	show the time taken to run a
program
e.g. time ftp
(display the time taken to execute
ftp)
times	show the uptime of the sell
e.g. times
(display the system uptime)
tload	show a graphic report of the system
load
e.g. tload
(show the currentsystem load average to a specified
process)
top	list the top active or specified
process e.g. top -p pid
(-p:display specific process by pid)
touch	update timestamp for an existing file
e.g. touch myfile.txt
(modify myfile.txt to the current
time)
touch -t	update timestamp for an existing file
e.g. touch –t myfile.txt
(-t: specify a time)
tr	translates sets of characters
e.g. echo apple	tr “apple” “banana”
(output: banana)
traceroute*	trace the route to a host
e.g. traceroute xvauhdhxv.com
(trace packets route to another host)
trap	run a command on receiving a
signal
e.g. trap
(display the current signal traps)
tree -p	list directory contents in tree format
e.g. tree –p
(-p: also show the file permissions)
tty	show the name of the terminal
device e.g. tty
(show the terminal filename)
type	detect the type of a command
e.g. type wait
(output: wait is a shell builtin)
ulimit -a	limit user resources
e.g. ulimit -a
(-a:display all limits for the system)
umask	show or set the file permission value
e.g. umask 0022
(allow user read,
write privileges and all others to
read)
umask	show or set the file permission value
e.g. umask 0002
(allow group read,
write privileges and all others to
read)
umask	show or set the file permission value
e.g. umask 0077
(allow user read,
write privileges and no for others)
umount	unmount a device or filesystem
e.g. umount devdvd
( unmount a device DVD )
unalias	remove an alias
e.g. unalias aliasname
( delete a specified alias)
uname -a	show the current system information
e.g. uname -a
( -a: display all information)
uname -n	show the current system information
e.g. uname -n
( -n: display the host name)
unexpand	convert spaces into tabs
e.g. unexpand myfile.txt
(convert spaces to tabs for
myfile.txt)
uniq	filter out repeated lines in a file
e.g.
uniq myfile.txt
(show unique line in myfile.txt)
unset	remove shell variable or function
e.g. unset var
(delete a variable)
unzip	uncompress files from zip format
e.g. unzip archive.zip
(uncompress file from archive.zip)
uptime	show system uptime
e.g. uptime
(display system uptime)
useradd *	add a new user account
e.g. useradd username
(create a user account)
useradd* -d	the display default value for new users
e.g. useradd -d
(show default data for a new user)
userdel *	delete an existing user account
e.g. userdel username
(remove a user account)
usermod* -d	modify home directory
e.g. usermod -d homemydir andy
(-
d: specify home directory for andy.)
usermod * -l	modify an existing user account
e.g. usermod -l oldname newname
(-
l: login name change)
usermod * -p	modify an existing user account
e.g. usermod
-p password username
(-p:modify password of a user)
users	display current logged-in users
e.g. users
(list users currently logged in)
vdir	verbosely show directory contents
e.g. vdir
(vdir just like ls, but more verbose)
vi	open the vi text editor
e.g. vi filename
(open a file with vi text editor)
vmstat	report virtual memory statistics…
e.g. vmstat
(also report swap, disk i/o
devices…)
w	list current processes for each user
e.g. w username
(show the user’s process)
w -s	list current processes by summary
e.g. w -s
(-s: show a summary of shell
process)
wait	wait for a process to change state
e.g. wait 10788
(wait for 10788 to change state)
watch	execute a command periodically
e.g. watch –n 5 date
(-n5:update date every 5 seconds)
wc	show word count, line count, etc
e.g. wc myfile.txt
(list word, line count… for
myfile.txt)
wc -c	show word count, line count, etc
e.g. wc –c myfile.txt
(-c: show the byte counts)
wget	download a web page from a website
e.g. wget xvfwkaljo.com
(download webpage from above url)
wget -c	download a web page from a
website
e.g. wget –c examp.com
(-c: continue download previous
web)
whatis	show the manual page of a command
e.g. whatis ping
(show manual page of ping)
whereis	locate the source, man for a command
e.g. whereis ls
(show source, man locations of ls)
which	show path of an executable command
e.g. which ftp
(show the full path of
ftp command)
who	show who is currently logged in
e.g. who
(list all logged-in users, date,
time…)
who -a	list all users currently logged in
e.g. who -a
(-a: all information)
whoami	show the current user’s login name
e.g. whoami
(show your own user name)
whois	show the domain owner’s information
e.g. whois xvqizx.com
(list xvqizx.com owner’s
information)
write	write a message to another user
e.g. write username
(then write your message…)
xargs	execute a command with arguments
e.g. find -name " a. "	xargs rm
(find files named a., remove
them)
xcalc	launch a graphical calculator
e.g. xcalc
(open a scientific calculator)
xclock	launch graphical clock
e.g. xclock -digital
(-digital: specify a digital clock)
yes	output a string repeatedly until
killed
e.g. yes “hello”
(output hello repeatedly until killed)
yum	rpm-based package manager
e.g. yum install update
(install a package named "update")
zcat	output compressed text
e.g. zcat myfiles.txt.gz	less
(uncompress file and show contents)
zless	show un/compressed file contents
e.g. zless myfile.txt.gz
(zless: show contents by page)
zmore	show un/compressed file contents
e.g. zmore myfile.txt.gz
(zmore: show contents by screen)
zip	compress files to zip format
e.g. zip documents *
(create documents.zip for all files)
unzip	uncompress files from zip format<br
e.g. unzip myfile.zip
(uncompress myfile.zip.)

GIT-Essential-Commands

Here is a more complete cheat sheet of Git commands:

Initializing a Repository:

command	Explanation
configuration :
`$ git config [--global]` `user.name` `"<name>"`	Add username
`$ git config [--global]` `user.email` `"<email address>`	Add User email id
`$ git config --list`	To show config info
`$ git init`	Initializes a new local repository.
`$ git clone [url]`	Creates a copy of a remote repository on your local machine. [cloning]
---------Committing Changes: ------------
`$ git status`	Shows the status of the working directory.
`$ git add [file]`	Adds a file to the staging area.
`$ git add .`	Adds all changes in the working directory to the staging area.
`$ git add -A`	add all tracked files and untracked files from the workspace into index
`$ git rm <file1><file2>...`	To delete a tracked file in the index
`$ git rm --cached ..."	Move tracked file in the index into the workspace and untrack it
`$ git commit -m "[message]"`	Creates a new commit with the changes in the staging area.
`$ git commit -am "[message]"`	Adds all changes in the working directory and creates a new commit with the given message.
`$ git commit --amend .. -m "New message"`	Recommit the previous commit with newly changed file and commit message
tags :
`git tag`	Show all tags
`git tag -a <tag_flag> -m "tag comment message"`	Create a new tag at the current commit object
`git tag -a <tag_flag> <commit_id> -m "tag comment message`	Create a new tag at the specified commit object
`git show <tag_flag>`	show specific tag info in detail
undo modifies
`$ git checkout <filename>`	Discard tracked file's modification in the workspace
`$ git reset HEAD <file name>`	Move the added file from the index into the workspace
`$ git reset --soft <commit-id>`	Reset code with --soft, changes in the index and workspace are reserved
`$ git reset --mixed <commit id>`	Reset code with --mixed, changes in the index are discarded, however, changes in the workspace are reserved
`$ git reset --hard <commit-id>`	Reset code with --hard, changes in the index and workspace are discarded
`$ git revert <commit-id>`	Revert code and create a new commit object for this operation in this way, it will not overlap the commit history
`$ git revert HEAD~1`	Undo the previous commit changes and create a new commit object for this operation
------------------------Branching:--------------
`$ git branch`	Shows the current branch and all branches.
`$ git branch -a`	List all branches in the local repository and remote repository
`$ git branch -vv`	List all the local branch info in detail
`$ git branch [branch_name]`	Creates a new branch with the given name.
`$ git branch <branch-name> <commit id>`	create a new branch with a specified commit
`$ git checkout [branch_name]`	Switches to the branch with the given name.
`$ git merge [branch_name]`	Merges the changes from the branch with the given name into the current branch.
`$ git branch -d [branch_name]`	Delete the branch with the given name
`$ git branch --set-upstream-to=origin/<remote-branch-name> <local branch name>`	To build a tracking relationship between the local branch and the remote branch
`$ git branch --unset-upstream <local branch-name>`	cancel the tracking relationship between the local branch and the remote branch
`$ git diff <branch1> <branch2> --stat`	List the changed files between the two branches
Viewing History:
`$ git log`	Shows the commit history.
`git log --pretty=short`	Show all commit logs in the shot format
`git log --pretty=oneline`	One line show one commit log
`git log --stat`	Show all changed files in every commit log
`git log --follow <file-name>`	Show the change history of the specified file
`git log -p`	Show all diff info between two adjacent commit
`git blame <file-name>`	show who changed the file
`git reflog`	Show the recently commit log and branch checkout log
`$ git diff`	Shows the differences between the working directory and the last commit.
`$ git show [commit_hash]`	Shows the changes made in the commit with the given hash.
Remote Repositories:
`$ git remote -v`	Lists all remote repositories.
`$ git remote show <remote>`	show specified remote repo info
`$ git remote add [remote_name] [url]`	Adds a new remote repository with the given name and URL.
`$ git push [remote_name] [branch_name]`	Pushes the current branch to the remote repository.
`$ git pull [remote_name] [branch_name]`	Fetches the changes from the remote repository and merges them into the current branch.
`$ git push <remote> [local branch]:[remote-branch]`	Push local repo changes to the remote repo
`$ git push -u <remote> [local-branch]:[remote-branch]`	set -u parameter and build the tracking relationship between the local repo and the remote repo
`$ git push <remote> :[remote-branch]`	Delete remote branch in the remote repo
`$ git fetch [remote_name]`	Fetches changes from the remote repository, but doesn't merge them.
Managing conflicts
`$ git diff`	Shows the conflicts in the file
`$ git diff --base [file]`	Show the base version of the file before the merge
`$ git diff --ours [file]`	Show the version of the file you have locally
`$ git diff --theirs [file]`	Show the version of the file in the remote repository
`$ git merge --abort`	Abort the merge and go back to the state before the merge
Git Merge/Rebase
`git merge <branch-name>`	Merge the branch into the current branch
`$ git rebase <branch-name>`	rebase into branch
`$ git checkout <feature-branch> <br>`$ git rebase master`<br>`$ git checkout master`<br>`$ git merge `	Rebase Frequently usage
`$ git rebase --abort`	Abort rebase
suggestion: Don't rebase the master branch into your personal feature branch	The golden rule of Rebasing
`$ git diff --base <file-name>`	Conflicts against base file
Other
`$ git stash`	Temporarily save changes you've made but don’t want to commit yet
`$ git stash list`	Shows a list of all stashes
`$ git stash pop`	restore the last stash and remove it from the list
`$ git stash apply`	apply the stash without removing it from the list
save it and share with all your friends and collegues	A collection by G.Nagacharan with ❤️

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#day12 #90DaysOfDevops #git #github #linux #DevOps

day 12 of #90daysofdevops

Linux and GIT cheatsheets

All essential Linux commands

GIT-Essential-Commands

day 12 of #90daysofdevops

Linux and GIT cheatsheets

All essential Linux commands

GIT-Essential-Commands

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