Linux Command Cheatsheet

Package Managers

Debian (Ubuntu) uses apt | RedHat (CentOS) uses yum

List processes

ps aux
# a = show processes for all users
# u = display the process's user/owner
# x = also show processes not attached to a terminal

List processes by CPU usage

top

Amount of free memory

free

Memory, paging, processes, IO, CPU, and disk scheduling

vmstat

List files

ls

Long List, all files, sort by timestamp

ls -lat
# long list
# all files
# sort by timestamp

List files in another directory

ls ~
ls /
lr -r
# recursive

Shutdown Program

SIGNUP (SIGnal Hang Up)

sudo kill <processId>

Forcefully Terminate (SIGKILL)

sudo kill -9 <processId>

Make directories

mkdir one two three

Make nested directories

mkdir -p one/two

Remove directories

rm -r dir1 dir2

Force deletion/surpress errors

rm -f dir1 dir2

Create file

touch one.txt two.txt three.txt

Remove files

rm file.txt file2.txt

How long the system's been up for

uptime

Network & IO

iostat
netstat -a

Services (daemons)

sudo systemctl enable [service]
sudo systemctl start [service]
sudo service [service] start
systemctl status [service]

List all environment variables

printenv

Return last status code

echo $?

Install sysstat

Free swap

sar -S

List drives/devices

sudo lsblk
sudo blkid
suod df -h

Print Working Directory

pwd

Determine type of file

file one.txt

Display history of commands

history

Search History

grep = Global Regular Expression Print

history | grep git

Search History with spaces

history | grep 'git commit'

Recall command (enter to execute)

history !5

Clear history

history -c

Get the word count from a file

wc filename

Type of command

type ls
whatis cp

Multiple commands/same line (semi-colon executes all valid cmds)

mkdir folder1;touch file1;mv file1 folder1

&& short circuits remaining commands upon an invalid command

cal && DATE && mkdir testing

Copies files starting with an alpha carchater to dir1

cp f?l*.txt dir1

apples, bananas, carrots, hundred, face, 123
cp [abc]* dir1

Copies files not starting with alpha cars to dir2

apples, bananas, carrots, hundred, face, 123
cp [!abc]* dir2

Copy filenames starting with an f to dir1

file1.txt, file2.txt, file3.txt, job.txt
cp f?l\*.txt dir1

Copy filenames beginning with an uppercase letter

cp [[:upper:]]* dir1

Copy files beginning with a lowercase character

cp [[:lower:]]* dir1

Copy files beginning with an alpha character

cp *[[:alpha:]] dir1

Copy files beginning with a digit

cp *[[:digit:]] dir1

copy files beginning with alpha-numeric characters

cp *[[:alnum:]] dir1

Copy files beginning with digit and ending with alpha character

cp [[:digit::]]*[[:alpha:]] dir1

Copy files which do not begin with a digit

cp [![::digit:]]* dir1

Add Alias

vi ~/.bashrc

Create alias command

type todo - check if command exists, first

alias todo=”cd Desktop; vi file.txt”
alias rename=”mv”

Delete an alias

unalias rename

tar = Tape Archive

Unpack a tar file

• x = extracts from zip file
• v = verbose
• z = decompress files
• f = filename you’re working with

tar -xvf file.tar

Execute File System Check on Startup

sudo touch /forcesck

Kernal Data

uname -a