Linux Commands Summary

Commands

Command	Description
alias	Simplify commands
apropos	Search for related commands
arch	Check computer architecture
arp	Query IPs in the same subnet
at	Set task execution time
atd	Execute scheduled tasks
awk	Process specific pattern strings
a2p	Convert to Perl file
badblocks	Check for bad blocks
bc	Run calculator
biff	Check mail reception with sound
bg	Set background
bind	Bind keys or function sequences
break	Exit a loop
cal	Check calendar
bubuiltin	Check internal commands
case	Process conditional clauses
cat	View file on screen
cd	Change directory
cfdisk	Configure disk
chattr	Change file attributes
chfn	Change user information
chgrp	Change file/directory group ownership
chmod	Change file permissions
chown	Change file owner
chsh	Change assigned shell
cksum	Check CRC value
clear	Clear terminal screen
clock	Adjust CMOS time
cmp	Compare files
colcrt	Character conversion filter
colrm	Delete columns
column	Horizontal alignment
comm	Compare and output files
command	Verify commands
continue	Continue loop
cp	Copy files
cpio	Create backup copies
crontab	Manage cron
csplit	Set format and rules for files
curl	Download/upload data via HTTP (command line data transfer tool)
cut	Output only required fields
date	Check date
dd	Read and write block devices
debugfs	Debug ext2 file system
declare	Declare variables
df	Check file system usage
dirs	Display directory list
dmesg	Check boot messages
dnsdomainname	Print DNS name
domainname	Print and set NIS name
du	Check directory and file sizes
dumpe2fs	Check file system information
echo	Standard output
eject	Eject device
elm	Mail related
enable	Specify internal commands
env	Print environment variables
eval	Read arguments
exec	Execute shell commands
exit	Exit
expand	Convert tabs to spaces
export	Set variables
e2fsck	Repair file system
fc	Receive specified editor
fdformat	Format floppy disk
fdisk	Partition disk
fg	Start specified job as foreground process
file	Check file type
find	Search for files
finger	Check user information
fold	Format text
fmt	Format text
for	Execute loop
free	Check memory usage
fsck	Check file system
fstab	Store static file system information
ftp	File transfer program
fuser	Print process ID
getkeycodes	Print mapping table
grep	Search for specific strings
gzexe	Compress executable files
gzip	Compress files
halt	Shut down system
hash	Remember/index
head	Output beginning of file
help	Show help
host	Check host information
history	Check command history
hostname	Query server name
id	Check account information
if	Execute conditional statement
ifconfig	Assign address to network card
imolamod	Install module
inetd	Top-level daemon for internet services
init	Set run level
ispell	Check spelling
jobs	Check running processes
kbd_mode	Print keyboard mode
kill	Force terminate process
klogd	Kernel log daemon for force termination
ldd	Check shared library dependencies
less	Output page by page
let	Express regular expressions
lilo	Boot
ln	Create links
locate	Find files matching pattern
login	Log in
logger	Record system logs
logname	Show user login name
logout	Exit login shell
look	Search for specific words
losetup	Check duplicate devices
lpd	Print daemon
lpq	Print current print job status
lpr	Print
lprm	Delete documents in queue
ls	List directory contents
lsattr	Show file system attributes
lsdev	Print hardware devices
lsmod	Print module information
lnsmod	Load module
rmmod	Unload module
mail	Mail related
make	Compile
man	View manual
mattrib	Change MS-DOS file attributes
mbadblocks	Check hard disk bad blocks
mcd	Change MS-DOS directory
mcopy	Copy files between Linux and DOS
mdel	Check server model in Linux
mdeltree	Delete MS-DOS files
mdirmesg	Check if messages can be received
mformat	Format MS-DOS file system disk
mkdir	Create directory
mke2fs	Create file system
mkfs	Create file system
mknod	Create special files
mkswap	Set swap area
mlabel	Change file system label
mmd	Create MS-DOS file system directory
mount	Assign device to specific file/folder
more	Output screen by screen
mrd	Delete MS-DOS file system directory
mutt	Mail related
mv	Move files
netstat	Check current network status
nice	Change process priority
od	View file in octal
passwd	Enter password
pidof	Find process ID of running program
pine	Mail related
ping	Check network
popd	Cancel pushd
ps	Check process status
pstree	Check process relationships
pwd	Check absolute path
quota	Check disk quota
rarp	Manage rarp table
rcp	Copy files to remote host
rdev	Inspect and set root, swap device, RAM size, video mode
rdate	Set time via network
reboot	Reboot
readonly	Mark as read-only
renice	Change process priority
reset	Reset terminal
restore	Restore data
rlogin	Direct login
rm	Delete files
rmdir	Delete directory
route	Add/delete routing table
rpm	Add/remove programs
rpm2cpio	Convert rpm to cpio
rsh	Execute commands remotely
rup	Print host status
rusers	Print users logged into host
rwall	Broadcast message to host users
rz	PC -> Server (Download files from server using ZMODEM)
script	Record
set	Set variable values
setup	Configure system settings
showmount	Show host mount information
shutdown	Power off
sleep	Pause briefly
source	Interpret script
split	Split files
ssh	Encrypted remote login
stty	Show terminal line settings
su	Switch account
suspend	Suspend shell
swapoff	Disable swap
swapon	Enable swap
sync	Reset buffer
syslogd	Configure login process
sz	Server -> PC (Send files to server using ZMODEM)
tac	View in reverse
tail	Output end of document
talk	Chat
tar	Bundle files
tcpdchk	Configure tcp wrapper
tcpmatch	Predict network requests
tee	Create standard output from standard input
telnet	Remote access
test	Test
times	Print user and system time in shell
top	Show CPU process status
tr	Replace strings
true	Return exit code
type	View type
ul	Display with underline
ulimit	Set limits
umask	Set mask mode
umount	Disconnect device
unalias	Remove alias
uname	View system information
unexpand	Convert spaces to tabs
uniq	Find duplicate lines
useradd	Create user account
userdel	Delete account
usermod	Modify user account information
unset	Unset configured variable
uptime	Check system load average
users	Check logged-in users
w	Check status of users connected to the system
wait	Wait for process
wall	Send message to all users
wc	Count characters, words, and lines
whatis	View brief description of command
while	Loop command
who	Check users
write	Send simple message on console
xcopy	Copy repeatedly
ypchfn	chfn command used in NIS
ypchsh	chsh command used in NIS
yppasswd	passwd command used in NIS
zcat	View compressed file
zcmp	Compare compressed files
zforce	Force create gz file
zgrep	Run grep on compressed files
zmore	Run more on compressed files
znew	Recompress .Z file to .gz

Options

Option	Description
-h (--human-readable)	Convert to human-readable format
--max-dept=1	Set depth ex) du -h --max-depth=1
-l	To see the information in the long list format

Examples

Command	Description
grep -o 'price:[0-9]+' ./FILE.csv >> ../RESULT.txt	Find the numeric part after price: in FILE.csv and save it to RESULT.txt
grep -o -i 'price:' RESULT.txt | wc -l	Print total count of price in RESULT.txt file
awk 'a[$1] == "" { a[$1]="X" } END { print length(a) }' RESULT.txt	Print count of non-duplicate lines in RESULT.txt file