← Shell Initiation

First we need to open "the gate" to this world of shadows.

CMD + SPACE_LINE 
"Terminal" [ENTER]

You are seen to the hostname follow by the path where you are and after all that your name.

Last login: DD MMM XX HH:MM:SS on ttysXXX 
HOSTNAME:PATH USER$

The $ sign tells you that it's waiting for commands.

Before starting this trip a couple of tools that are going to be handy.

1. TAB key

Unix it's case sensitive. That's means it's not the same to write cd desktop than cd Desktop. So you probably want to type precise commands. For that you can use the embedded auto completion. How? With your TAB_KEY.

For example:

HOSTNAME:PATH USER$ cd De[TAB_KEY]
HOSTNAME:PATH USER$ cd Desktop

Not just that also it let you see the different options you have Do:

HOSTNAME:PATH USER$ cd [TAB_KEY][TAB_KEY]
.DS_Store       Library/        Movies/         Sites/      Applications/ 
.Trash/         Music/          Pictures/       Desktop/    Documents/ 
.MacOSX/        Public/         Downloads/
HOSTNAME:PATH USER$ cd 

Voila! you get all the possible directories.

The same happened to the commands. Try start typing two words and it will show you all the commands that starts with that letters. Also if there are to many options it will ask you if you still want to see them.

2. Use history

Typing it's hard, specially when it's non-sense. So it's good to know how to go back on your steps to take a look of what you have done.

• You can use the history program:

    HOSTNAME:PATH USER$ his[TAB_KEY] 
    HOSTNAME:PATH USER$ history

• Also you can go through your history using the UP_KEY**.

    HOSTNAME:PATH USER$ [UP_KEY]
    HOSTNAME:PATH USER$ history

• If you are searching for a specific command you can find it by pressing CONTROL+R**

    HOSTNAME:PATH USER$ [COTROL_KEY]+r
    (reverse-i-search)`': history 

  Then you can type the beginning of the command and that's going to try to guess what command are you tracking.

• If you want to repeat your last command just type !!. If you remember the exactly numbers of previous command you can do !-1.

3. Be on CONTROL

Here you have some keyboard Shortcuts that will make you feel like a real dungeon master:

3.a. Control Process

We will talk about process on the future but its good to know this from the beginning

• Ctrl + C Kill whatever you are running

• Ctrl + Z Puts whatever you are running into a suspended background process. fg restores it.

3.b. Control your entry

• Ctrl + D Exit the current shell

• Ctrl + L Clears the Screen, similar to the clear command

• Ctrl + U Clears the line before the cursor position. If you are at the end of the line, clears the entire line.

• Ctrl + A Go to the beginning of the line you are currently typing on

• Ctrl + E Go to the end of the line you are currently typing on

• Ctrl + W Delete the word before the cursor

• Ctrl + K Clear the line after the cursor

• Ctrl + R Let’s you search through previously used commands

• TAB Auto-complete files and folder names

3.c. Control your terminal

• Cmd + N New Terminal Windows

• Cmd + RIGHT and Cmd + LEFT Jump between windows

• Cmd + [NUMBER] go directly to the terminal windows [NUMBER]

• Cmd + shift + w close Terminal windows

• Cmd + t New Tab Terminal

• Cmd + Shift + right and Cmd + Shift + left Jump between windows

• Cmd + w Close Tab

• Cmd + up line up

• Cmd + down line down

4. Read the manual

Unix systems are designed for engineers as all they do the makes manuals for it. Unix have a embedded manual. Just type man followed by the name of the program and you will get the manual for it. Use key for navigate throughout it and after that press q to quit.

Here are some commands that will give you always good and handy information:

• man Displays manual pages

• info Displays command information pages

• pwd Shows the current directory the user is in.

• df Display free disk space

• du Display disk usage statistics

• file FILENAME Identifies the file type (binary, text, etc).

• find FILENAME DIRECTORY Finds a file/directory. More reference: here

• which FILENAME Shows the location of a file if it is in your PATH.

• whereis FILENAME Shows the location of a file.

• apropos Locate commands by keyword lookup

• whatis Search the whatis database for complete words.

• tty Print current terminal name

• stty Set terminal options

• printenv Display value of a shell variable

• time Time a simple command or give resource usage

• uptime System Load Average

• cal Displays a calendar and the date of easter