The /var filesystem
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# The `/var` filesystem

The `/var` contains data that is changed when the system is running normally. It is specific for each system, i.e., not shared over the network with other computers.

`/var/catman`
  A cache for man pages that are formatted on demand. The source for manual pages is usually stored in `/usr/man/man*` ; some manual pages might come with a pre-formatted version, which is stored in `/usr/man/cat*` . Other manual pages need to be formatted when they are first viewed; the formatted version is then stored in `/var/man` so that the next person to view the same page won't have to wait for it to be formatted. (`/var/catman` is often cleaned in the same way temporary directories are cleaned.)
`/var/lib`
  Files that change while the system is running normally.
`/var/local`
  Variable data for programs that are installed in `/usr/local` (i.e., programs that have been installed by the system administrator). Note that even locally installed programs should use the other `/var` directories if they are appropriate, e.g., `/var/lock` .
`/var/lock`
  Lock files. Many programs follow a convention to create a lock file in `/var/lock` to indicate that they are using a particular device or file. Other programs will notice the lock file and won't attempt to use the device or file.
`/var/log`
  Log files from various programs, especially `login` (`/var/log/wtmp` , which logs all logins and logouts into the system) and `syslog` (`/var/log/messages` , where all kernel and system program message are usually stored). Files in `/var/log` can often grow indefinitely, and may require cleaning at regular intervals.
`/var/run`
  Files that contain information about the system that is valid until the system is next booted. For example, `/var/run/utmp` contains information about people currently logged in.
`/var/spool`
  Directories for mail, news, printer queues, and other queued work. Each different spool has its own subdirectory below `/var/spool` , e.g., the mailboxes of the users are in `/var/spool/mail` .
`/var/tmp`
  Temporary files that are large or that need to exist for a longer time than what is allowed for `/tmp` . (Although the system administrator might not allow very old files in `/var/tmp` either.)

Next: The /proc filesystem Up: Overview of the Directory Previous: The /usr filesystem