Using UNIX from a Macintosh OS X Computer

You may not realize it, but your Mac already runs a variant of UNIX. You can easily access a terminal window to use your computer's built-in UNIX functionality with the "Terminal" program (Applications/Utilities/ You may want to make a shortcut to this program in your Dock, since you'll be using it a lot from now on. Similarly, you can use your Mac directly to log into a UNIX server, and even to transfer files to/from a UNIX server.

Logging into an UNIX server

The standard protocol for logging into a modern UNIX server is through using a Secure SHell (SSH) client. OS X has built-in SSH functionality, through the 'ssh' command on the Terminal.

To use ssh from the Terminal:

For additional information on using ssh, type

man ssh

(short for manual) in the Terminal window.

Enabling X11-Forwarding (Popping up windows form the UNIX server)

Your Mac comes with another program that enables you to display graphics from programs running on a remote UNIX/Linux server, called "X11" (Applications/Utilities/ If this program is not currently installed on your Mac, it is available on the OS X installation DVD that came with your computer -- install this program.

To enable forwarding, just run before starting You may close the xterm window that pops up and use, or you may use this X11 terminal instead. Once X11 is running, when you log into remote UNIX servers (using the -Y option to ssh above), you should be able to display remote graphics.

Transferring files to and from a UNIX server (terminal)

You may copy files to and from a UNIX/Linux server in the Terminal window as well, using the 'scp' command. The syntax is either

scp file_to_copy_from username@hostname:file_to_copy_to


scp username@hostname:file_to_copy_from file_to_copy_to

depending on whether you want to copy the file to or from the UNIX server. For example, suppose I have a file named 'file1' in my home directory on titan, and I want to copy it to the current directory on my Mac (the one the terminal is in, type 'pwd' to see which directory you are in if unsure):

scp .


scp file1

would give the desired result. Suppose now that I have the file 'file2' in the current directory on my Mac that I want to copy to my home directory on titan:

scp file2


scp file2

would do the trick. For more information on the 'scp' command, type man scp in the terminal.

Transferring files to and from a UNIX server (graphical)


The most popular graphical file transfer option in OS X is the program Fetch. This is not free, although SMU users can download it for free from the IT web site.

To use Fetch, fill in the UNIX hostname (e.g., your username on that host (e.g. reynolds), and your password on that host, then click 'Connect'. You will then see a display of your remote directory on the UNIX server. Transfer files by dragging them to and from the Finder.


A free alternative to Fetch is FileZilla. To install FileZilla:

To use FileZilla, fill in the fields for the host (e.g., your username on that host (e.g. reynolds), your password, and the port (use 22 for SFTP), and hit [return]. You should notice two file browser windows open up, the browser on the left is on your computer, the browser on the right is from the UNIX host (e.g. titan). Transfer files by dragging them from one computer to the other with your mouse.

D.R. Reynolds, 20 January 2009