Quota Command and Disk Tidying

The quota command with no options will tell you if your disk usage exceeds your quota. Use quota -v to list actual disk usage and quota information regardless of whether limits have been exceeded. Note that each filesystem has its own set of quotas. Normally you will only be allocated disk space on the filesystem which contains your home directory.

To list all the files you have in your own filespace along with their sizes, type

cd ; ll -Ra | more [ That's ell ell, not eleven - it stands for "long listing"]

Pay particular attention to the 5th field of the ll output - this is the file size in bytes.

-rw-------   1 xyz99      ugrad          647 Jul 29 13:03 patran.ses.01
-rw-------   1 xyz99      ugrad          647 Jul 29 13:52 patran.ses.02
-rw-------   1 xyz99      ugrad          477 Jul 29 13:54 patran.ses.03
-rw-------   1 xyz99      ugrad       620026 Jul 18 14:10 raid.ps
-rw-------   1 xyz99      ugrad      1925120 Sep 28 21:12 spon
-rw-------   1 xyz99      ugrad      2356792 Sep 28 21:15 spon2
-rw-------   1 xyz99      ugrad      5643780 Sep 28 21:17 spon3

Note that a simple file listing (using "ll") will not show files or directories beginning with a "." - always use "ll -a" when investigating quota problems.

Files can be deleted using the unix rm command:

rm spon

will delete the file "spon" in the current directory.

rm spon*

will delete all files in the current directory beginning with "spon" regardless of what characters follow it. Be careful when using wildcards, it's easy to delete more than you intend. A slightly safer version of the above is:

rm -i spon*

which asks for confirmation before deleting each file. This is the system default behaviour for new users, but if you have your own startup file or use a shell other than the system default (/usr/bin/sh) this may not be the case.

When trying to save disk space you should concentrate on removing very large files, especially executable programs and old plotfiles. Of particular note are files called "core". These can be extremely large and are generally the result of a crashed program. Their practical usefulness is limited and removal is recommended.

Web browser cache files have a significant effect on quota usage, particularly if using more than one of the available "flavours" of Teaching System machine (i.e. HP-UX, Linux or Windows). Mozilla (or a descendant such as Firefox) are the browsers of choice on the Teaching System. Help with Mozilla configuration (including clearing the cache) can be found here.

Most browsers' "preferences" dialogues will provide the option the clear the cache and it's a good idea to do this fairly frequently.

The tidydisk command may be used to find and selectively remove all files larger than some given size. With no arguments it locates all files larger than 100,000 bytes in your HOME directory and all sub-directories. To set a different file size and directory use ( for example)

tidydisk -s 5000 matlab/plots

which finds all files larger than 5000 bytes in directory matlab/plots.

[University of Cambridge] [Engineering Department] [Computing Help]

Updated on 9th October 1997

Stephen Mounsey, sjm@eng.cam.ac.uk