Backup on Linux
If your linux-box is not running CentOS installed by the IT-department (a laptop or a desktop with another Linux installed by yourself) then you should know that files are only stored on you local harddisk and there is no backup of any kind! Please read below and pick the solutions that fit your work.
Version control systems (VCS)
For text files like code and LaTeX files, an VCS is ideal. You have a local copy of the file organized in folders and then you push changes you make to those files to repository in the cloud somewhere. One of the most popular tools for this is Git. You can find several hosting services that you can use for storing your repository for free:
File syncronization services
Get some storage in the cloud and syncronize your files with the cloud and your other computers. Here are some options with both for free and paid for storage:
A very simple solution it to just copy the files you don't want to risk loosing to Fysik's file server. You can do that with the scp command:
$ scp filename email@example.com:foldername
Use man scp to learn more.
Mount the Fysik file-server
Example using sshfs:
$ mkdir camp $ sshfs xxx.fysik.dtu.dk:/home/camp/username camp
RSYNC - the file-copying tool
To back up everything in the foldername/ folder (remember the backslash /) to the backup folder on the Fysik file server:
$ rsync -av folder/ xxx.fysik.dtu.dk:backup
If you want a nice tool to handle backups that has a graphical user interface then a popular tool is Déjà Dup. It is the default backup solution for Ubuntu.