squid - HTTP web proxy caching server


   squid [-dhisrvzCFNRSVYX] [-l facility ] [-f config-file ] [-[au] port ]
   [-k signal ] [-n service-name ] [-O command-line ]


   squid is a high-performance  proxy  caching  server  for  web  clients,
   supporting  FTP, gopher, ICAP, ICP, HTCP and HTTP data objects.  Unlike
   traditional caching software, Squid handles all requests in  a  single,
   non-blocking process.

   Squid  keeps meta data and especially hot objects cached in RAM, caches
   DNS lookups, supports non-blocking DNS lookups, and implements negative
   caching of failed requests.

   Squid  supports  SSL,  extensive  access  controls,  and  full  request
   logging.  By using the lightweight Internet Cache Protocols  ICP,  HTCP
   or  CARP,  Squid  caches  can  be  arranged  in a hierarchy or mesh for
   additional bandwidth savings.

   Squid consists of a main server program squid , some optional  programs
   for  custom  processing  and  authentication,  and  some management and
   client tools.  When squid starts up, it spawns a configurable number of
   helper  processes,  each  of  which can perform parallel lookups.  This
   reduces the amount of time the cache waits for results.

   Squid is derived from the ARPA-funded Harvest Project.

   This manual page only lists the command line arguments.  For details on
   how  to  configure Squid see the file /etc/squid/squid.conf.documented,
   the Squid wiki FAQ and examples at  http://wiki.squid-cache.org/  ,  or
   the  configuration  manual  on  the  Squid  home page http://www.squid-


   -a port     Specify HTTP port number  where  Squid  should  listen  for
               requests,  in  addition  to any http_port specifications in

   -C          Do not catch fatal signals.

   -d level    Write debugging to stderr also.

   -f file     Use the given config-file instead of  /etc/squid/squid.conf
               .   If  the  file  name  starts  with  a !  or | then it is
               assumed to be an external command or command line.  Can for
               example  be used to pre-process the configuration before it
               is being read by Squid.   To  facilitate  this  Squid  also
               understands  the  common  #line notion to indicate the real
               source file.

   -F          Don't serve any requests until store is rebuilt.

   -h          Print help message.

   -i          Install as a Windows Service (see -n option).

   -k reconfigure | rotate | shutdown | interrupt | kill | debug | check |
               Parse  configuration file, then send signal to running copy
               (except -k parse ) and exit.

   -l facility Use specified syslog facility. Implies -s

   -n name     Specify Windows Service name to use for service operations,
               default is: Squid

   -N          No daemon mode.

   -O options  Set Windows Service Command line options in Registry.

   -r          Remove a Windows Service (see -n option).

   -R          Do not set REUSEADDR on port.

   -s          Enable    logging   to   syslog.   Also   configurable   in

   -S          Double-check swap during rebuild.

   -u port     Specify ICP port number (default: 3130), disable with 0.

   -v          Print version and build details.

   -X          Force full debugging.

   -Y          Only return UDP_HIT or UDP_MISS_NOFETCH during fast reload.

   -z          Create missing swap directories and other missing cache_dir
               structures,  then  exit.  All  cache_dir  types  create the
               configured top-level directory  if  it  is  missing.  Other
               actions  are  type-specific. For example, ufs-based storage
               systems create missing L1 and  L2  directories  while  Rock
               creates the missing database file.

               This  option does not enable validation of any present swap
               structures. Its focus is on creation of missing pieces.  If
               nothing  is  missing,  squid  -z just exits. If you suspect
               cache_dir  corruption,  you  must  delete   the   top-level
               cache_dir directory before running squid -z.

               By   default,  squid  -z  runs  in  daemon  mode  (so  that
               configuration  macros  and  other  SMP  features  work   as
               expected). Use -N option to overwrite this.


   Squid configuration files located in /etc/squid/:

          The  main configuration file. You must initially make changes to
          this  file  for  squid  to  work.  For  example,   the   default
          configuration  only allows access from RFC private LAN networks.
          Some packaging distributions block even that.

          Reference copy of the configuration file. Always kept up to date
          with the version of Squid you are using.

          Use  this  to  look  up  the  default configuration settings and
          syntax after upgrading.

          Reference copy of the configuration file. Always kept up to date
          with the version of Squid you are using.

          Use  this  to  read  the documentation for configuration options
          available in your  build  of  Squid.  The  online  configuration
          manual  is  also  available  for  a  full  reference of options.

          The main configuration file for the web cachemgr.cgi tools.

          The main configuration file for the Sample MSNT authenticator.

          CSS Stylesheet to control the display of generated error  pages.
          Use  this to set any company branding you need, it will apply to
          every language Squid provides error pages for.

   Some files also located elsewhere:

   /usr/share/squid/mime.conf (mime_table)
          MIME type mappings for FTP gatewaying

          Location of Squid error pages and templates.


   Squid was written over many years by a changing team of developers  and
   maintained  in  turn  by  Duane  Wessels <duane@squid-cache.org> Henrik
   Nordstrom  <hno@squid-cache.org>  Amos  Jeffries   <amosjeffries@squid-

   With  contributions  from  many  others  in  the  Squid community.  see
   CONTRIBUTORS for a full list of individuals who contributed code.   see
   CREDITS for a list of major code contributing copyright holders.


    *   Copyright   (C)   1996-2015  The  Squid  Software  Foundation  and
    * 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 on the usage of this program can be sent to the  Squid  Users
   mailing list <squid-users@squid-cache.org>


   Bug  reports  need  to  be  made  in  English.   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@squid-cache.org>

   Report  ideas for new improvements to the Squid Developers mailing list


   cachemgr.cgi (8), squidclient (1), pam_auth (8),  squid_ldap_auth  (8),
   squid_ldap_group (8), ext_session_acl (8), squid_unix_group (8),
   The Squid FAQ wiki http://wiki.squid-cache.org/SquidFaq
   The Squid Configuration Manual http://www.squid-cache.org/Doc/config/



Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.

Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.

Free Software

Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.

Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.

Free Books

The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.

Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.


Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.

Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.