Terminal Basics

Here you'll be given a quick Terminal tutorial outlining some introduction commands and inputs to give you a better grasp on the command line.

Following the instructions below in order will give you a step-by-step instruction that should get you up to speed with the basics of using the Terminal.

Navigation

Input	Command
Up Arrow Key	Cycle through command history.
Tab	Autocomplete command.
ls	List all files in directory.
cd [directory]	Change current directory.
pwd	Print current (working) directory.
~/	The user's home directory.
./	Current directory location.
open [file/ directory]	Open file through default application.
open ./	Open current directory with Finder.
clear	Wipe current Terminal screen.
ctrl+C	Cancel out of the current command.

Navigating through the Terminal is very similar to navigating through your Finder. Think of it as a less visual version of your Finder window.

Keyboard commands

The Terminal is radically different from the standard OS GUI in that there's no mouse controls. Everything will be entirely operated from keyboard commands.

Here's a quick list of some common commands:

Enter - Execute the currently written command.
Left & Right Arrow keys - Scroll through characters in the current command string.
Up & Down Arrow keys - Cycle through previous commands history. Use the up arrow to cycle back through history, down to cycle forward.
Tab - Autocomplete a string entry you're currently typing.
Ctrl+C - Used to kill a process, intercepted by a program so it can clean its self up before exiting, or not exit at all. Simply put, it'll quit from a process if you're currently within one.

pwd

Just like in your Finder window, your Terminal is always currently "residing" within a folder. Folders are known as directories within command line. To see what directory you currently are within on the command line, you can enter the command pwd (Print Working Directory).

$ pwd
/Users/admin/Desktop

ls

Similar to the Finder, you can also see all the current files and folders within your current directory without influencing them. To see a list of files within your current directory, you can use the command ls .

$ ls
planets earth sun.jpg galaxy.txt

cd

To navigate around the Terminal, you won't want to reside within the same directory forever. To change to another a directory, you can do so with the command cd.

$ cd planets
$ pwd
/Users/admin/Desktop/planets

$ cd ../
$ pwd
/Users/admin/Desktop

clear

Every now and then the Terminal will get rather messy. Once in a while it's simply best to clean the board and start anew. To do so, simply type clear as below:

$ clear

Manipulating files

Once you have a better grasp of how to navigate around the command line, it's time to start manipulating and editing files.

Input	Command
touch	Create empty file within current directory.
mkdir	Make directory.
cat	Print current contents of file.
rm	Delete file.
rm -r	Delete directory.
mv	Move file or directory.
wc	Get word count from file.
grep	Search a file for a patterns.

touch

touch, in it's default state where we'll be using it, is the equivalent of creating an empty file.

$ ls
file.txt
$ touch hello.txt
$ ls
file.txt hello.txt

mkdir

mkdir is used to Make Directories.

$ ls
file.txt hello.txt
$ mkdir folder1
$ ls
file.txt hello.txt folder1

cat

cat is used to inspect the contents of file.

$ cat file.txt
hello world

mv

mv is used to move a file between directories.

$ ls
file.txt hello.txt folder1
$ mv hello.txt folder1
$ ls
file.txt folder1

rm

rm is used to delete or remove a file.

$ ls
file.txt folder1 badfile.txt
$ rm badfile.txt
$ ls
file.txt folder1

Be careful when using this command as it instantly deletes a file, with no means of recovery. The file is not sent to your trashbin.

rm -r

rm is used to delete or remove a file.

$ ls
file.txt folder1
$ rm folder1.txt
$ ls
file.txt

Be careful when using this command as it instantly deletes a file, with no means of recovery. The file is not sent to your trashbin.

wc

wc can be used to gather the word count from a file.

$ cat file.txt
hello world
$ wc file.txt 
0       2      11 file.txt

grep

grep, short for "Globally search a Regular Expression and Print", can be used to search for a pattern within a string and print the corresponding line of code.

$ grep hello file.txt
hello world

Pipes

Piping allows the user to connect different commands and the outputs of commands together.

Input	Command
\|	Pass the output of one command directly to another.
>	Write the output of one command to a document.
>>	Append the output of one command to a document.

|

Used as the default pipe structure, allowing you to string the output from one command into another.

$ cat file.txt | grep hello.txt

>

Used to write the output from one command into another file.

Note: This will replace any current file contents without warning, be careful when using.

$ cat hello.txt
hello_world1
hello_world2
$ cat file.txt
single line of text
$ grep world hello.txt >file.txt
$ cat file.txt
hello_world1
hello_world2

>>

Used to append the output from one command into another file.

$ cat hello.txt
hello_world1
hello_world2
$ cat file.txt
single line of text
$ grep world hello.txt >>file.txt
$ cat file.txt
single line of text
hello_world1
hello_world2

Fun Commands

curl

Pull data from a URL (Client URL).

Outputted markup in example has been slightly altered for display purposes.

$ curl www.google.com 

 302 Moved
 302 Moved
 The document has moved
 HREF="http://www.google.nl/?gfe_rd=cr&ei=9GirVontD5O-oQeUvaugCA">here