The Hackr

Linux Terminal Cheat Sheet

A cheat sheet is a list of the commands which we use most in Linux. Master the command line to perform any task in Linux just within few keystrokes!

Bash Commands

uname -a — Show system and kernel
head -n1 /etc/issue — Show distri­bution
mount — Show mounted filesy­stems
date — Show system date
uptime — Show uptime
whoami — Show your username
man command — Show manual for command

Bash Shortcuts

CTRL-c — Stop current command
CTRL-z — Sleep program
CTRL-a — Go to start of line
CTRL-e — Go to end of line
CTRL-u — Cut from start of line
CTRL-k — Cut to end of line
CTRL-r — Search history
!! — Repeat last command
!abc — Run last command starting with abc
!abc:p — Print last command starting with abc
!$ — Last argument of previous command
ALT-. — Last argument of previous command
!* — All arguments of previous command
^abc^123 — Run previous command, replacing abc with 123

Bash Variables

env — Show enviro­nment variables
echo $NAME — Output value of $NAME variable
export NAME=value — Set $NAME to value
$PATH — Executable search path
$HOME — Home directory
$SHELL — Current shell

IO Redire­ction

cmd < file — Input of cmd from file
cmd1 <(cmd2) — Output of cmd2 as file input to cmd1
cmd > file — Standard output (stdout) of cmd to file
cmd > /dev/null — Discard stdout of cmd
cmd >> file — Append stdout to file
cmd 2> file — Error output (stderr) of cmd to file
cmd 1>&2 — stdout to same place as stderr
cmd 2>&1 — stderr to same place as stdout
cmd &> file — Every output of cmd to filet
cmd > file — Standard output (stdout) of cmd to file

Pipes

cmd refers to a command

cmd1 | cmd2 — stdout of cmd1 to cmd2
cmd1 |& cmd2 — stderr of cmd1 to cmd2

Command Lists

cmd1 ; cmd2 — Run cmd1 then cmd2
cmd1 && cmd2 — Run cmd2 if cmd1 is successful
cmd1 || cmd2 — Run cmd2 if cmd1 is not successful
cmd & — Run cmd in a subshell

Directory Operations

pwd — Show current directory
mkdir dir — Make directory dir
cd dir — Change directory to dir
cd .. — Go up a directory
ls — List files

ls Options

-a — Show all (including hidden)
-R — Recursive list
-r — Reverse order
-t — Sort by last modified
-S — Sort by file size
-l — Long listing format
-1 — One file per line
-m — Comma-­sep­arated output
-Q — Quoted output

Search Files

grep pattern files — Search for pattern in files
grep -i — Case insens­itive search
grep -r — Recursive search
grep -v — Inverted search
grep -o — Show matched part of file only
find /dir/ -name name* — Find files starting with name in dir
find /dir/ -user name — Find files owned by name in dir
find /dir/ -mmin num — Find files modifed less than num minutes ago in dir
whereis command — Find binary / source / manual for command
locate file — Find file (quick search of system index)

File Operations

touch file1 — Create file1
cat file1 file2 — Concat­enate files and output
less file1 — View and paginate file1
file file1 — Get type of file1
cp file1 file2 — Copy file1 to file2
mv file1 file2 — Move file1 to file2
rm file1 — Delete file1
head file1 — Show first 10 lines of file1
tail file1 — Show last 10 lines of file1
tail -F file1 — Output last lines of file1 as it changes

Watch a Command

watch -n 5 'ntpq -p' — Issue the'ntpq -p'command every 5 seconds and display output

Process Management

ps — Show snapshot of processes
top — Show real time processes
kill pid — Kill process with id pid
pkill name — Kill process with name name
killall name — Kill all processes with names beginning name

Nano Shortcuts

Files
Ctrl-R — Read file
Ctrl-O — Save file
Ctrl-X — Close file
Cut and Paste
ALT-A — Start marking text
CTRL-K — Cut marked text or line
CTRL-U — Paste text
Navigate File
ALT-/ — End of file
CTRL-A — Beginning of line
CTRL-E — End of line
CTRL-C — Show line number
CTRL-_ — Go to line number
Search File
CTRL-W — Find
ALT-W — Find next
CTRL-\ — Search and replace

Screen Shortcuts

screen — Start a screen session
screen -r — Resume a screen session
screen -list — Show your current screen sessions
CTRL-A — Activate commands for screen
CTRL-A c — Create a new instance of terminal
CTRL-A n — Go to the next instance of terminal
CTRL-A p — Go to the previous instance of terminal
CTRL-A " — Show current instances of terminals
CTRL-A A — Rename the current instance

More screen info at: http:/­/ww­w.g­nu.o­rg­/so­ftw­are­/sc­reen/

File Permis­sions

chmod 775 file — Change mode of file to 775
chmod -R 600 folder — Recurs­ively chmod folder to 600
chown user:group file — Change file owner to user and group to group

File Permission Numbers

First digit is owner permis­sion, second is group and third is everyone.

Calculate permission digits by adding numbers below.

4 — read (r)
2 — write (w)
1 — execute (x)

Sreehas

The hacking trend these days has definitely turned criminal because of e-commerce ¯\_(ツ)_/¯

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