3.6. 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/cache/man

A cache for man pages that are formatted on demand. The source for manual pages is usually stored in /usr/share/man/man?/ (where ? is the manual section. See the manual page for man in section 7); some manual pages might come with a pre-formatted version, which might be stored in /usr/share/man/cat* . Other manual pages need to be formatted when they are first viewed; the formatted version is then stored in /var/cache/man so that the next person to view the same page won't have to wait for it to be formatted.

/var/games

Any variable data belonging to games in /usr should be placed here. This is in case /usr is mounted read only.

/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/mail

This is the FHS approved location for user mailbox files. Depending on how far your distribution has gone towards FHS compliance, these files may still be held in /var/spool/mail.

/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 news, printer queues, and other queued work. Each different spool has its own subdirectory below /var/spool, e.g., the news spool is in /var/spool/news . Note that some installations which are not fully compliant with the latest version of the FHS may have user mailboxes under /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.)