Basic UNIX commands reminder

Connecting to the front-end machines of the clusters:
Note: you have to replace <user_name> with your UNIL user name.

• ssh <user_name>@wally-front1.unil.ch
• ssh <user_name>@axiom-front1.unil.ch

Navigating the directory tree:

• pwd print's the current working directory. Useful to see where you currently are.
• cd <directory> change working directory to <directory>.
• cd .. move one directory up.
• cd ~ change working directory to your home directory.

List the content of a directory: Note: if you don't specify any <directory> in the commands below the content of the current directory is listed.

• ls <directory> list content of specified directory.
• ls -l <directory> list content in greater details.

Creating and copying/moving files and directories:

• mkdir <directory name> create a new directory.
• touch <new file> create an empty file named .
• mv <file> <destination> moves <file> to the specified <destination>
• cp <file> <copy name> creates a copy of <file> named . if is a directory then the file is copied to the specified directory and keeps the same name as the original.
• cp -r <directory> <new path> copies an entire <directory> to the specified new location.

Copying files from a local machine to the cluster: The following command will copy <fileName> to your home directory in the cluster. To copy files to a different directory, replace ~ with the /path/where/to/copy/files

• scp <fileName> <userName>@wally-front1.unil.ch:~

Display file content in terminal:

• cat <file> prints the entire content of <file> to the terminal.
• less <file> opens <file> with the less program where you can scroll down/up the file. Press q to exit less. This is useful to look at larger files.
• head <file> print the first 10 lines of <file> to the terminal.
• tail <file> print the last 10 lines of <file> to the terminal.

Simple text editors available on most GNU-Linux machines:

• nano: follow the instructions given at the bottom of the terminal, e.g. Ctrl + o to save your edits and Ctrl + x to exit nano.
• vim: press i to enter edit mode and Esc to exit edit mode. In the non-edit mode, press :wq to save your edits and exit vim, or :q/:q! to exit without saving your changes.

Change file permissions:

• chmod a+x <file> add execution permissions to file.
• chmod a-x <file> remove execution permissions to file.
• chmod a+w <file> add write permissions to file.
• chmod a-w <file> remove write permissions to file.

If you need more background information on UNIX, the following e-learning module is available here.