File and Navigating

ls, list, print the contents of the current directory

., current directory

.., parent directory

~, home directory

-, previous directory

/, root

cd, change directory

pwd, print working directory

mkdir, make directory

rm, remove file

rmdir, remove directory

cp, copy

mv, move or rename

touch, update access date of a file or directory, if not existing, create one

Read

echo, print out

cat, concatenate, read file and write to stdout

more or less, view file screen by screen

grep, global regular expression print, for searching

diff, show difference, diff fileA fileB

find, find files, eg. find . -name '*.jpg' -exec mv {} ./jpg \;

Process

ps, process status, aux for all

jobs, status of jobs

fg / bg, foreground / background a process, % with job number

&, suffix to run in background

ctrl-c, SIGINT, stop process

ctrl-\, SIGQUIT, quit process

kill -TERM <PID>, SIGTERM, exit gracefully

ctrl-z, SIGTSTP, pause process

Redirection

|, pipe output to input

<, redirect input

>, redirect output

>>, redirect output and append

Programs

sudo, super user do

which, find path for a program

date, print date and time

tee, read input and write to stdout and file

chmod, change mode, permission

man, manual

history, shell history

Environment Variable

env or printenv, print out environment variable

$PATH, path for programs

$SHELL, current shell

$HOME, home directory