computer science


Backing up and saving your files

As the tech support people know from bitter experience, students are forever accidentally deleting a vital file or forgetting to save a file they have spent hours on. Unix is not forgiving of this. It is impossible to retrieve such files. There are backups done nightly to disk and files can be restored to you very quickly off the backup drive, but that doesn't get you back work you have just lost.
Note that it takes a matter of hours and a lot of disk space to backup all the home directories. It is wasteful of resources if we have to back up (for example) core dumps, mp3 files, and directories full of downloaded source code which has nothing to do with coursework - not to mention gaming files. Be aware that such files may be deleted without notice .

So: make sure you save your work frequently, especially when you are working under pressure and on something important. (The emacs editor can keep a backup copy of the file you are editing automatically.) You can keep copies of your work yourself in your home directory, but please do not be excessive about this (and definitely, take care not to recursively backup your home directory).
To make backup copies of whole directories, use "tar" and "gzip". E.g. supposing you have created a cosc241 directory in your home directory in which to keep all your 241 coursework:

  • Make sure you are in your home directory (type "pwd" on the command-line and that will respond with a string of characters which tell you the path to your current working directory).
  • Type "tar cpf - cosc241 | gzip > cosc241.tar.gz".
    This creates an archive file of everything in your cosc241 directory, pipes ("|") it through the gzip compression application and redirects (">") it to a file (instead of the output going to your terminal window - which would be very messy).

If you do lose files, please send a message to the tech support group cshelp, specifying the creation and "deletion" dates, and someone will let you know whether your work can be retrieved.