Terminals, also known as command lines or consoles, allow us to accomplish and automate tasks on a computer without the > use of a graphical user interface. Using a terminal allows us to send simple text commands to our computer to do things like > navigate through a directory or copy a file, and form the basis for many more complex automations and programming skills.
(1). Open the Dash by clicking the Ubuntu icon in the upper-left, type terminal, and select the Terminal application from the results that appear.
(2). Hit the keyboard shortcut: Ctrl + Alt + T
To know more about a command and how to use it, use the man command. It shows the manual pages of the command.
For example, man man shows the manual pages of the man command. Typing in the command name and
the argument help it show which ways the command can be used (e.g., man --help)
binli@ubuntu:~$ man man
binli@ubuntu:~$ man --help
This command prints the location of your current working directory. It's important to know actually where you're before going to a parent or sub directories.
binli@ubuntu:~$ pwd
/home/binli
binli@ubuntu:~$
"~" - represent the home folder of the user, conventionally it would be /home/user/, where "user" is the user name can be anything like /home/binli.
"$" - is just a sign of the shell prompt, means that shell is ready to accept commands, you can understand it as a separator after which, you can interact with a shell. Can also be "#" which shows that root is the user who's session is going on.
binli@ubuntu:~$ sudo su -
[sudo] password for binli:
root@ubuntu:~#
ls is one of the most used basic linux commands, used to print contents of a directory, by default it lists contents of current working directory(pwd).
binli@ubuntu:~$ ls
Desktop Documents Downloads
Pictures Public Videos
binli@ubuntu:~$
Example, use ls /usr/bin to list contents of the /usr/bin folder.
Assume you are in /home/binli directory, you want to go to the /usr/local/share/fonts directory, use cd /usr/local/share/fonts.
binli@ubuntu:~$ pwd
/home/binli
binli@ubuntu:~$ cd /usr/local/share/fonts
binli@ubuntu:~$ pwd
/usr/local/share/fonts
You can create a blank file with touch command. As example, use touch hello_world.py to create a blank hello_world.py file under the your home directory.
binli@ubuntu:~$ touch hello_world.py
binli@ubuntu:~$ ls
Desktop Documents Downloads hello_world.py
Pictures Public Videos
The mkdir command creates new directories in your file system. Create a new directory called myfiles in the current directory.
binli@ubuntu:~$ mkdir myfiles
Creates the directory /home/binli/linux/command/myfiles. If any of the parent directories /home/binli/linux or /home/binli/linux/command, do not already exist, they will automatically be created.
binli@ubuntu:~$ mkdir -p /home/binli/linux/command/myfiles
The chmod command changes the permissions of files or directories. Only the file owner or a privileged user can change the access mode. In general, chmod commands take the form:
binli@ubuntu:~$ chmod 755 hello_world.py
Here the digits 7, 5, and 4 each individually represent the permissions for the user, group, and others, in that order. Each digit is a combination of the numbers 4, 2, 1, and 0:
4 stands for "read",
2 stands for "write",
1 stands for "execute", and
0 stands for "no permission".
You can copy files and directories with this command. Typical usage is like
binli@ubuntu:~$ cp hello_world.py hello_world_copy.py
To copy a directory, including all its files and subdirectories, to another directory.
binli@ubuntu:~$ cp -r Documents Documents-copy
Also don't forget to use proper path when you are coping something to different location.
The mv command is used to move or rename directories and files.
binli@ubuntu:~$ mv hello_world.py rename_hello_world.py
binli@ubuntu:~$ mv Documents-copy rename_Documents
The rm command is used to remove directory or files.
binli@ubuntu:~$ rm rename_hello_world.py
binli@ubuntu:~$ rm -r rename_Documents
To edit a file named helle_world.py, use the command:
binli@ubuntu:~$ vi rename_hello_world.py
to insert text, first move the cursor to the position where you want to insert (text is inserted before the cursor),
then press i . After that save your changes by press the Esc key then type :wq. If you do not want to save
the changes type :q! instead. For more information search on Google.
sudo stands for "SuperUser Do". So, if you want any command to be done with administrative or root privileges, you can use the sudo command. For example, if you want to edit a file like viz. /etc/init/network-manager.conf, which needs root permissions, you can use the command
binli@ubuntu:~$ sudo vi /etc/init/network-manager.conf
Use apt-get to install packages. This requires root privileges, so use the sudo command with it. For example, if you want to install the text editor vim, we can type in the command
binli@ubuntu:~$ sudo apt-get install vim”
Similarly, any exist packages can be installed like this. It is good to update your repository each time you try to install a new package. You can do that by typing
binli@ubuntu:~$ sudo apt-get update
binli@ubuntu:~$ sudo apt-get upgrade
binli@ubuntu:~$ sudo apt-get remove
or typing
binli@ubuntu:~$ sudo apt-get update
binli@ubuntu:~$ sudo apt-get dist-upgrade
The command apt-cache search is used to search for a package. If you want to search for one, you can type in apt-cache search vim (this doesn't require root).
Displays text, one screen at a time.
binli@ubuntu:~$ more /etc/init/network-manager.conf
Use hostname to know your name in your host or network. Basically, it displays your hostname and IP address.
binli@ubuntu:~$ hostname
ubuntu
binli@ubuntu:~$ hostname -I
128.xx.xx.xxx
[References]
[1]: https://www.computerhope.com/unix.htm