Remote Linux Server Tutorial

There are several Linux servers available to CS students for teaching purposes. The servers can be accessed through secure shell (SSH). The host name for the servers is cs-ssh.uwf.edu.

VS Code Remote SSH Mode

The easiest way to work with the remote server is to use the Remote - SSH extension in Visual Studio Code.

Steps:

1. Install Visual Studio Code on your computer.
2. Install the Remote - SSH extension in Visual Studio Code.
3. Click the light brown icon on the bottom left corner of the VS Code window and choose “Connect to Host…”
4. For the first time use:
   • Input the host name with user name uname@cs-ssh.uwf.edu
   • Choose Linux as the remote server type
   • Choose “Continue” to trust the server
   • Input your password
5. For future use, you can choose the host name from the list on your welcome page.

SSH client

You will need an SSH client to connect to the remote server. The standard command-line environments mostly come with a ssh command that you can invoke to connect to servers providing ssh service. These environments include the Terminal app available on Linux, macOS, and Windows Subsystem for Linux (WSL).

To connect to an SSH server on Windows without a terminal, you will need a standalone SSH client software. The most popular SSH client on Windows is Putty. You can find it free online and install it.

SSH command

You need to know the basic SSH command usage to connect to a remote server in your terminal. Use the following command and replace ``uname`` with your uwf email ID (part before @ in your UWF email address):

ssh uname@cs-ssh.uwf.edu

You will be asked if the server looked safe in your first attempt to connect. Just type yes. Then, input your password to log into the Linux.

You may add your public key to the server to avoid future hustle to input passwords. Read the ssh key-pair instructions on how to set up a key pair to use with SSH for instant login.

Typical SSH Errors

• Time out

  It is usually a network problem. You should check your internet connection. It may also be an IP ban caused by multiple failed password input. This can be solved by submitting a ticket to the help desk.

• Wrong password

  People tend to expect a cursor move when inputting the password. In terminal, you will always need to type passwords blindly. Or type in an editor and paste to the terminal window.

Work with Linux

Once you are logged in. You will be manipulating the remote Linux the same way as you can do with your local Linux in its terminal. You need some knowledge of basic Linux commands to do your work on the server. The common Linux commands can be found here.

ls

List all objects in a directory. Add the -l option to list in a long format. Add the -a option to list all including hidden objects. This command can be followed by a list of objects to be listed. Listing a directory will show objects in the directory. Listing a file object will list a single file.

cd

Change the working directory to a new location. You can use cd .. to change to the parent directory. .. represents the parent directory in Linux. Learn Linux directory structure for more information. A typical Linux path looked like /usr/lib/lab.so in which the slash symbol is the delimiter.

mkdir

Followed by a directory name to make a directory or a list of names to make several directories.

rm

Remove objects. Can remove files or directories. Add -r to remove a directory recursively.

man

Show the manual of a command. E.g. man ls to show the manual for the ls command.

./main

Run a program called main in the current directory. Must prefix with ./ before the name in which . represent the current directory in Bash. You can change main to the name of any program in the current directory to run it.

Refer to this Linux cheat sheet for more information.

Edit in the SSH window

Use vim editor

To edit a remote file directly in the terminal or SSH client window. You must use a command-line editor like vi, vim, nano, etc. vim is an enhanced vi editor and is widely used as a command-line text based editor. vim is extremely powerful, but at the same time hard to learn and master. Many programmers found it worth the time to learn it, including myself. You can learn several basic operations in vim to get it started to edit your code.

When you type the command vim main.cpp to edit a file called main.cpp in the current director, you will enter the full screen edit mode and your main.cpp file will be opened. You can press i key (case sensitive) to enter the insert mode and type your content. Press Esc to exit the insert mode and type :wq to save and quit.

To learn more about vim, check out the introduction to VI and VI cheatsheet documents.

The nano command can invoke a simpler text editor. You can learn how to use nano if you prefer a simpler editor.

File Transfer

As mentioned above, you can transfer locally-edited files to the server instead of creating and editing in the terminal window. There are many tools supporting file transferring through an SSH connection (SFTP):

• Command line tools: scp, rsync
• GUI tools: WinSCP (Windows only), FileZilla (All platforms)