Fast Shortcut

Ctrl + Alt + T = Open terminal
Ctrl + C = Kill Current Program
Crtl + Shift + C = Copy in terminal
Crtl + Shift + V = Paste in terminal
Tab = Auto-complete in terminal

Note when you press enter, as well as being executed, your text is saved in a command history. Use arrow keys to browse this history to avoid retyping commands.

Basics

When the shell is ready to receive instructions from you, it will display a prompt and a cursor.

Open your linux terminal (The shell) and you will see this.

1	user@hostname:~$

Hello World

1	$ echo "Hello"

$ represents your shell’s prompt.
$ at the beginning of the line is not something you need to type.

This command prints hello.

1	$ echo $USER

This command prints the user name.

1	$ hostname

This command prints the hostname.

Exit

$ exit

This command close the shell.
You can also press ^D (Control + D) to close the shell.

Looking around directories

Linux use / (whereas Windowas uses \ ) to separte components in the description of a file’s location.

Listing

$ ls

This command will list all the files in your currect directory (location).

$ ls -a

You can even force the shell to show you hidden files by adding -a (stand for “all”) to the command.

Move your location

$ cd /etc

Now you just moved from Home to a directory called “etc”.

Where am I?

print name of current/working directory.

1 2	$ pwd /etc

You can use this command to print the working directory.

Wildcards of finding files

You can get a focused list by indicating the patterns of names.

$ ls hos*

This command list all filenames in the working directory which begin with “hos”.

You can also add * in the middle.

1	$ ls c.conf g.conf

This command list all filenames in the working directory which begin with c or g and end in .conf. The * represents any number of messing characters.
so ls * does the same thing as ls.

To represent exactly one character, use ‘?’.

1	$ ls ???.conf

This command will show all .conf files with 8(3+.conf) characters in their names.

Back to Home

Go back to home directory

$ cd

you could also use:

$ cd ~

Listing files that not in your working directory

Example:

1 2	$ ls /etc $ ls /etc/*.conf

Remove files

1	$ rmdir <yourfile>

1	$ rm -rf <yourfile>

-r means “recursive” delete directories and contents.
-f means “force” dont ask any questions.

Renaming things

1	$ mv <filenname> <newfilenname>

Looking for things

Search file name

1	$ find . - name services

This command search a name called “service” in currect directory.

Search file content

1	$ grep play /etc/services

This command will output all the lines of /etc/services which contain “play”.

Cleaning up

For example, if we want to remove the “EEE” directory and everything under it, we can use this command:

be careful use this because linux has no undelete command.

1	$ rm -rf EEE

-r means “recursive” delete directories and contents.
-f means “force” dont ask any questions.

Permissions

The sudo command is required when performing actions that require root or superuser permissions, such as changing the password for another user.

1	sudo [commend]

Shutdown

1	$ shutdown now

You can even schedule a shutdown.

1	$ shutdown 23:00 Shutdown tonight at 23:00, save your work and log out before then!

If you dont put anything after “shutdown”, it will shutdown in a minute.

1	$ shutdown

Show Folder

1	$ nautilus .

Advanced

Ubuntu remove system error

1 2	$ ls -l /var/crash/ $ sudo rm /var/crash/*

Edit read-only file in /etc

1	$ sudo -H gedit <path to file>

Create a file from terminal

Method 1:

1	$ touch <filename>

Method 2:

1	$ cat <filename>

The file is created, but it’s empty and still waiting for the input from the user. You can type any text into the terminal, and once done CTRL-D will close it, or CTRL-C will escape you out.

Method 3:

1	$ > <filename>

Read file text

1	$ cat <filename>

Alternatively:

1	$ less <filename>

Print shared library dependencies

1	$ ldd <filename>

List contents of directories in a tree-like format

1	$ tree -L 2

Set file as executable

1	$ chmod +x <filename>

Check How does thing works like a boss!

tldr : The command replacing man
TLDR: Linux Man Pages Simplified
The tldr pages are a community effort to simplify the beloved man pages with practical examples.