Important commands from Learn Enough Command Line to Be Dangerous

Command	Description	Example
echo <string>	Print string to screen	$ echo hello
man <command>	Display manual page for command	$ man echo
⌃C	Get out of trouble	$ tail^C
⌃A	Move to beginning of line
⌃E	Move to end of line
⌃U	Delete to beginning of line
Option-click	Move cursor to location clicked
Up & down arrow	Scroll through previous commands
clear or ⌃L	Clear screen	$ clear
exit or ⌃D	Exit terminal	$ exit
>	Redirect output to filename	$ echo foo > foo.txt
>>	Append output to filename	$ echo bar >> foo.txt
cat <file>	Print contents of file to screen	$ cat hello.txt
diff <f1> <f2>	Diff files 1 & 2	$ diff foo.txt bar.txt
ls	List directory or file	$ ls hello.txt
ls -l	List long form	$ ls -l hello.txt
ls -rtl	Long by reverse modification time	$ ls -rtl
ls -a	List all (including hidden)	$ ls -a
touch <file>	Create an empty file	$ touch foo
mv <old> <new>	Rename (move) from old to new	$ mv foo bar
cp <old> <new>	Copy old to new	$ cp foo bar
rm <file>	Remove (delete) file	$ rm foo
rm -f <file>	Force-remove file	$ rm -f bar
up & down arrow keys	Move up or down one line
spacebar	Move forward one page
⌃F	Move forward one page
⌃B	Move back one page
G	Move to end of file
1G	Move to beginning of file
/<string>	Search file for string	/rose
n	Move to next search result
N	Move to previous search result
q	Quit less
curl	Interact with URLs	$ curl -O example.com
which	Locate a program on the path	$ which curl
head <file>	Display first part of file	$ head foo
tail <file>	Display last part of file	$ tail bar
wc <file>	Count lines, words, bytes	$ wc foo
`cmd1	cmd2`	Pipe cmd1 to cmd2
ping <url>	Ping a server URL	$ ping google.com
less <file>	View file contents interactively	$ less foo
grep <string> <file>	Find string in file	$ grep foo bar.txt
grep -i <string> <file>	Find case-insensitively	$ grep -i foo bar.txt
ps	Show processes	$ ps aux
top	Show processes (sorted)	$ top
kill -<level> <pid>	Kill a process	$ kill -15 24601
pkill -<level> -f <name>	Kill matching processes	$ pkill -15 -f spring
mkdir <name>	Make directory with name	$ mkdir foo
pwd	Print working directory	$ pwd
cd <dir>	Change to	$ cd foo/
cd ~/<dir>	cd relative to home	$ cd ~/foo/
cd	Change to home directory	$ cd
cd -	Change to previous directory	$ cd && pwd && cd -
.	The current directory	$ cp ~/foo.txt .
..	One directory up	$ cd ..
find	Find files & directories	$ find . -name foo*.*
cp -r <old> <new>	Copy recursively	$ cp -r ~/foo .
rmdir <dir>	Remove (empty) dir	$ rmdir foo/
rm -rf <dir>	Remove dir & contents	$ rm -rf foo/
grep -ri <string> <dir>	Grep recursively (case-insensitive)	$ grep -ri foo bar/

Miscellaneous keyboard symbols.

Key	Symbol
Command	⌘
Control	⌃
Shift	⇧
Option	⌥
Up, down, left, right	↑ ↓ ← →
Enter/Return	↵
Tab	⇥
Delete	⌫