purge(8) purge(8)
NAME
purge - magnifying glass into your squid cache
SYNOPSIS
purge [-a] [-c cf] [-d l] [-(f|F) fn | -(e|E) re] [-p h[:p]] [-P #]
[-s] [-v] [-C dir [-H]] [-n]
DESCRIPTION
purge is used to have a look at what URLs are stored in which file
within your cache. The purge tool can also be used to release objects
which URLs match user specified regular expressions. A more troublesome
feature is the ability to remove files squid does not seem to know
about any longer.
This is a tool for expert usage only, use it under your own responsi-
bility.
OPTIONS
-a a kind of "i am alive" flag. It can only be activated, if
your stdout is a tty. If active, it will display a little
rotating line to indicate that there is actually something
happening. You should not use this switch if you capture
your stdout in a file or if your expression list produces
many matches. The -a flag is also incompatible with the
(default) multi cache_dir mode.
default: off See also: -n
-c cd this option lets you specify the location of the squid.conf
file. Purge understands about more than one cache_dir, and
does so by parsing squid.conf. It knows about both ways of
Squid-2 cache_dir specifications, and will automatically
try to use the correct one.
default: /usr/local/squid/etc/squid.conf
-C cf if you want to rescue files from your cache, you need to
specify the directory into which the files will be copied.
Please note that purge will try to establish the original
server directory structure. This switch also activates
copy-out mode. Please do not use copy-out mode with any
purge mode (-P) other than 0.
For instance, if you specified "-C /tmp", purge will try to
recreate /tmp/www.server.1/url/path/file, and so forth.
default: off See also: -H, -P
-d l lets you specify a debug level. Different bits are reserved
for different output.
default: 0
-e|-E re Specify one regular expression to be searched for in the
cache. This is useful if there is only a handful of ob-
jects you want to check. Please remember to escape the
shell meta characters used in your regular expression. The
use of single quotes around your expression is recommended.
The capital letter version works case sensitive, the lower
caps version does not.
default: (no default)
-f|-F fn if you have more than a handful of expressions, or want to
check the same set at regular intervals, the file option
might be more useful to you. Each line in the text file
will be regarded as one regular expression. Again, the
capital letter version works case sensitive, the lower caps
version does not.
default: (no default)
-H if in copy-out mode (see: -C), you can specify to keep the
HTTP Header in the recreated file.
default: off See also: -C
-n tell purge to process one cache_dir after another, instead
of doing things in parallel. If you have more than one
cache_dir in your configuration purge will fork off a
worker process for each cache_dir to do the checks for op-
timum speed, assuming a decently designed cache. Since par-
allel execution will put quite some load on the system and
its controllers, it is sometimes preferred to use less re-
sources, though it will take longer.
default: parallel mode for more than one cache_dir
-p h[:p] Some cache admins use a different port than 3128. The purge
tool will need to connect to your cache in order to send
the PURGE request (see -P). This option lets you specify
the host and port to connect to. The port is optional. The
port can be a name (check your /etc/services) or number. It
is separated from the host name portion by a single colon,
no spaces allowed.
default: localhost:3128
-P # If you want to do more than just print your cache content,
you will need to specify this option. Each bit is reserved
for a different action. Only the use of the LSB is recom-
mended, the rest should be considered experimental.
no bit set: just print
bit#0 set: send PURGE for matches
bit#1 set: unlink object file for 404 not found PURGEs
bit#2 set: unlink weird object files
If you use a value other than 0 or 1, you will need to slow rebuild
your cache content. A warning message will remind you of that. If you
use bit#1, all unsuccessful PURGEs will result in the object file in
your cache directory to be removed, because squid does not seem to know
about it any longer. Beware that the asyncio might try to remove it af-
ter the purge tool, and thus complains bitterly. Bit#1 only makes
sense, if Bit#0 is also set, otherwise it has no effect (since the HTTP
status 404 is never returned).
Bit#2 is reserved for strange files which do not even contain a URL.
Beware that these files may indicate a new object squid currently in-
tends to swap onto disk. If the file suddenly went away, or is removed
when squid tries to fetch the object, it will complain bitterly. You
must slow rebuild your cache, if you use this option.
It is recommended that if you dare to use bit#1 or bit#2, you should
only grant the purge tool access to your squid, e.g. move the HTTP and
ICP listening port of squid to a different non-standard location during
the purge.
default: 0 (just print)
-s If you specify this switch, all commandline parameters will be
shown after they were parsed.
default: off
-v be verbose in the things reported about the file. See the output
section below.
CONFIGURATION
In order to use purge to affect a running proxy with PURGE method, you
will have to enable this feature in squid.conf. By default, PURGE is
disabled. You should watch closely for whom you enable the PURGE abil-
ity, otherwise a total stranger just might wipe your cache content.
Lines similar to the following will need to be added to your
squid.conf:
acl purge method PURGE
http_access allow localhost purge
http_access deny purge
Reconfigure or restart (preferred) your squid after changing the con-
figuration file.
OUTPUT
In regular mode, the output of purge consists of four columns. If the
URL contains not encoded whitespaces, it may look as if there are more
columns, but the last one is the URI.
# name meaning
= ====== ===========================================================
1 file name of cache file eximed which matches the regular expres-
sion.
2 status return result of purge request, " 0" in print mode.
3 size object size including stored headers, not file size.
4 uri perceived uri
Example for non-verbose output in print-mode:
/cache3/00/00/0000004A 0 5682 http://graphics.user-
friendly.org/images/slovenia.gif
In verbose mode, additional columns are inserted before the uri. Time
stamps are reported using hexadecimal notation, and Squid's standard
for reporting "no such timestamp" == -1, and "unparsable timestamp" ==
-2.
# name meaning
= ====== ===========================================================
1 file name of cache file eximed which matches the re.
2 status return result of purge request, " 0" in print mode "-P 0".
3 size object size including stored headers, not file size.
4 md5 MD5 of URI from file, or "(no_md5_data_available)" string.
5 ts UTC of Value of Date: header in hex notation
6 lr UTC of last time the object was referenced
7 ex UTC of Expires: header
8 lr UTC of Last-Modified: header
9 flags Value of objects flags field in hex, see: Programmers Guide
10 refcnt number of times the object was referenced. 11 uri
STORE_META_URL uri or "strange_file" Example for verbose output in
print-mode: /cache1/00/00/000000B7 0 406
7CFCB1D319F158ADC9CFD991BB8F6DCE 397d449b 39bf677b ffffffff 3820abfc
0460 1 http://www.netscape.com/images/nc_vera_tile.gif
KNOWN ISSUES
Purge does not slow rebuild the cache for you.
It is still relatively slow, especially if your machine is low on mem-
ory and/or unable to hold all OS directory cache entries in main mem-
ory.
Should never be used on "busy" caches with purge modes higher than 1.
TODO
1) use the stat() result on weird files to have a look at their ctime
and mtime. If they are younger than, lets say 30 seconds, they were
just created by squid and should not be removed.
2) Add a query before purging objects or removing files, and add an-
other option to remove nagging for the experienced user.
3) The reported object size may be off by one.
AUTHOR
This program and manual was written by Santiago Garcia Mantinan
<manty@debian.org> Amos Jeffries <amosjeffries@squid-cache.org>
Based on original squidpurge README.
COPYRIGHT
* Copyright (C) 1996-2023 The Squid Software Foundation and contribu-
tors
*
* Squid software is distributed under GPLv2+ license and includes
* contributions from numerous individuals and organizations.
* Please see the COPYING and CONTRIBUTORS files for details.
QUESTIONS
Questions on the usage of this program can be sent to the Squid Users
mailing list <squid-users@lists.squid-cache.org>
REPORTING BUGS
See http://wiki.squid-cache.org/SquidFaq/BugReporting for details of
what you need to include with your bug report.
Report bugs or bug fixes using http://bugs.squid-cache.org/
Report serious security bugs to Squid Bugs <squid-bugs@lists.squid-
cache.org>
Report ideas for new improvements to the Squid Developers mailing list
<squid-dev@lists.squid-cache.org>
SEE ALSO
squid(8), squidclient(1) cachemgr.cgi(8)
October 12, 2014 purge(8)
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