Common Commands Cheat Sheet by mmorykan

Shebang - "­#!b­in/­bas­h" - First line of bash script. Tells script what binary to use

# - Creates a comment

hello_int = 1 - Treats "­1" as a string

Use lowerc­ase­_wi­th_­und­ers­cores for regular variables

mktemp - Creates temporary random file

bash -x - Prints commands and their arguments

exit value - Exits the script with value exit code

-z variable - Decides if variable is empty

$# - Stands for the number of arguments passed

-f filename - Determines if filename is a file

$1, $2, $3 - Refers to the first, second, and third arguments

-lt - Means <

-gt - Means >

dirname - Prints directory name of of argument

while [[ condition ]]; do stuff; done

until [[ condition ]]; do stuff; done

for word in ${words} - traverses each element in array

for ((;;)) - Is infinite for loop

for ((coun­ter=1; counter -le 10; counte­r++)) - Loops 10 times

${array[]} - References the whole array. Can also use @*

myasso­car­ray­=([­app­le]­="re­d" [banan­a]=­"­yel­low­") - Creates associ­ative array

unset array[I] - Deletes the I index

${#array} - Outputs the length of the array

home() { do stuff ; } Creates the home function

local - Creates local variable within function

git add <fi­len­ame> - Adds the file to git

git push - Pushes all git files to host

dnf install - Installs package

dnf remove - Removes package

systemctl stop - Stops systemd service

systemctl reload - Reloads systemd service config­uration files

systemctl disable - Disable systemd service

atq - Displays currently scheduled commands

atrm - Remove scheduled commands

journalctl - Shows logs

history - Shows previous commands

route - Configures IP connection

netstat -rn - Gives routing table

ip addr - Shows different addresses and internet connec­tions

wget - Downloads file from internet

Ctrl - C - Aborts command

fg - Resumes command after suspension

cal - Prints ASCII calendar

df - Reports file system disk space usage

fdisk - Manipu­lates disk partition table

top - Display and update sorted info about processes

passwd - Sets password for new user

chsh --shell /bin/sh username - Changes shell

chown - Changes owner

chmod - Changes permis­sions

chmod 1777 filename - Sets all permis­sions and a sticky bit

ls -a - Shows all files including hidden files in current directory

cd - Changes curent directory

ps - Report a snapshot of current processes

cp filename newfil­ename - Creates new file with old file inform­ation

mv - Moves files

rm - Remove­s\d­eletes files

rm -r directory/ - Removes directory

mkdir - Creates direct­ories

echo text >> filename - Moves text into file

touch - Creates any kind of file

less - Views files instead of opening them. Lets user scroll through

awk '{print $1,$2,$3}' filename - Prints first, second, third words of each line

vi filename - Opens text editor for file. Hard to use

more filename - Displays file contents (no scrolling)

find - Finds files

rmdir - Removes direct­ories

yes - Displays the same line of text until interr­upted