Cleaning Up

With my desktop machine's last system upgrade, I changed how I managed my /tmp directory. Before the upgrade, my configuration mounted a tmpfs on /tmp at startup, but now, it mounts a separate ext2 partition for /tmp. Linux implements the tmpfs filesystemtype in swap, making the contents of the directory really temporary; files and directories in such a filesystem vanish on reboot. But, now with the ext2 filesystem, /tmp files and directories stick around. This means that I now needed something to clean up my /tmp directory on a regular basis. So, I wrote a short script to do just that.

The script is just a series of find(1) commands that search a configuration-selected set of temporary directories and delete policy-selected files, symlinks, sockets, and directories. It is not a complex script, and, as such, is easy enough to modify for new circumstances.

The script (called /usr/local/sbin/cleantmp.sh) looks like:

#!/bin/bash
# cleantmp.sh - Remove unused files from tmp directories
# V1.1	- 2012-04-04

# ------------- Default Configuration --------------------
# TMP_DIRS - List of directories to search
# FILE_AGE - # days ago (rounded up) that file was last accessed
# LINK_AGE - # days ago (rounded up) that symlink was last accessed
# SOCK_AGE - # days ago (rounded up) that socket was last accessed

TMP_DIRS="/tmp /var/tmp /usr/src/tmp /mnt/tmp"
FILE_AGE=+1
LINK_AGE=+1
SOCK_AGE=+1

# Make EMPTYFILES true to delete zero-length files
EMPTYFILES=false
#EMPTYFILES=true

# === Change Log ===
# 2012-04-04	Added Change Log to script
#		Defined EMPTYFILES with value "false" (NB: 
#		Conditionally delete empty files, based on
#		  return value from /usr/bin/$EMPTYFILES

#-----------------------------------------------------------------
cd /
/usr/bin/logger "cleantmp.sh[$$] - Begin cleaning tmp directories"

# delete any tmp files that are more than 2 days old
/usr/bin/find $TMP_DIRS                                         \
     -depth                                                     \
     -type f -a -ctime $FILE_AGE                                \
     -print -delete

# delete any old tmp symlinks
/usr/bin/find $TMP_DIRS                                         \
     -depth                                                     \
     -type l -a -ctime $LINK_AGE                                \
     -print -delete

if /usr/bin/$EMPTYFILES ;
then
# delete any empty files
/usr/bin/find $TMP_DIRS                                         \
     -depth                                                     \
     -type f -a -empty                                          \
     -print -delete
fi

# Delete any old Unix sockets
/usr/bin/find $TMP_DIRS                                         \
     -depth                                                     \
     -type s -a -ctime $SOCK_AGE -a -size 0                     \
     -print -delete

# delete any empty directories (other than lost+found)
/usr/bin/find $TMP_DIRS                                         \
     -depth -mindepth 1                                         \
     -type d -a -empty -a ! -name 'lost+found'                  \
     -print -delete

/usr/bin/logger "cleantmp.sh[$$] - Done cleaning tmp directories"
exit 0

In /etc/cron.hourly, I have a symlink to this cleantmp.sh script, so that, hour-by-hour, the script will keep my temporary file directories clean and neat. Now, I know that my /tmp directory won't take up space with unnecessary files and directories, and all with just a little scrpiting knowledge.

Note: The previous version of cleantmp.sh automatically deleted zero-length ("empty") files from the specified directories, regardless of their atime. Michel Eillebrecht (mjm@wxs.nl) reported to me that this seems to cause problems with certain software build platforms (slackbuild, with make, for instance) which depend on generating temporary zero-length files, and later filling them with code. Should the older cleantmp.sh script run during the critical time, these files disappear, causing the build to fail. V1.1 of cleantmp.sh does not delete zero-length files, unless explicitly set to do so by the sysadmin. To enable "empty" file deletion, set the $EMPTYFILES variable to "true" (for /usr/bin/true); to disable, set it to "false" (for /usr/bin/false).

A patch file is included below to convert the old cleantmp.sh into the new script. Patch the old script by using the patch(1) command: patch cleantmp.sh <cleantmp.txt