Provided by: unicorn_5.4.1-2_amd64 bug


       unicorn - a rackup-like command to launch the Unicorn HTTP server


       unicorn [-c CONFIG_FILE] [-E RACK_ENV] [-D] [RACKUP_FILE]


       A  rackup(1)-like command to launch Rack applications using Unicorn.  It is expected to be
       started in your application root (APP_ROOT), but the "working_directory" directive may  be
       used in the CONFIG_FILE.

       While  unicorn  takes  a myriad of command-line options for compatibility with ruby(1) and
       rackup(1), it is recommended to stick to the few command-line  options  specified  in  the
       SYNOPSIS and use the CONFIG_FILE as much as possible.


       This  defaults  to  "" in APP_ROOT.  It should be the same file used by rackup(1)
       and other Rack launchers, it uses the Rack::Builder DSL.

       Embedded command-line options are mostly  parsed  for  compatibility  with  rackup(1)  but
       strongly discouraged.


       -c, --config-file CONFIG_FILE
              Path to the Unicorn-specific config file.  The config file is implemented as a Ruby
              DSL, so Ruby code may executed.  See  the  RDoc/ri  for  the  Unicorn::Configurator
              class  for  the  full list of directives available from the DSL.  Using an absolute
              path for for CONFIG_FILE is recommended as it makes multiple instances  of  Unicorn
              easily distinguishable when viewing ps(1) output.

       -D, --daemonize
              Run  daemonized  in  the  background.  The process is detached from the controlling
              terminal and stdin is redirected to "/dev/null".  Unlike many common UNIX  daemons,
              we  do  not  chdir  to  "/"  upon  daemonization  to  allow  more  control over the
              startup/upgrade process.  Unless specified in the CONFIG_FILE,  stderr  and  stdout
              will also be redirected to "/dev/null".

       -E, --env RACK_ENV
              Run under the given RACK_ENV.  See the RACK ENVIRONMENT section for more details.

       -l, --listen ADDRESS
              Listens  on  a  given  ADDRESS.   ADDRESS  may be in the form of HOST:PORT or PATH,
              HOST:PORT is taken to mean a TCP socket and PATH is meant to be a path  to  a  UNIX
              domain  socket.   Defaults  to  "" (all addresses on TCP port 8080) For
              production  deployments,  specifying  the  "listen"  directive  in  CONFIG_FILE  is
              recommended    as    it    allows    fine-tuning    of    socket    options.    -N,
       Disables  loading  middleware  implied  by  RACK_ENV.   This  bypasses  the  configuration
       documented  in  the  RACK  ENVIRONMENT  section,  but still allows RACK_ENV to be used for
       application/framework-specific purposes.


       -o, --host HOST
              Listen on a TCP socket belonging to HOST, default is "" (all addresses).  If
              specified  multiple  times on the command-line, only the last-specified value takes
              effect.  This option only exists for compatibility with the rackup(1) command,  use
              of "-l"/"--listen" switch is recommended instead.

       -p, --port PORT
              Listen  on the specified TCP PORT, default is 8080.  If specified multiple times on
              the command-line, only the last-specified value takes  effect.   This  option  only
              exists  for compatibility with the rackup(1) command, use of "-l"/"--listen" switch
              is recommended instead.

       -s, --server SERVER
              No-op, this exists only for compatibility with rackup(1).


       -e, --eval LINE
              Evaluate a  LINE  of  Ruby  code.   This  evaluation  happens  immediately  as  the
              command-line is being parsed.

       -d, --debug
              Turn on debug mode, the $DEBUG variable is set to true.

       -w, --warn
              Turn on verbose warnings, the $VERBOSE variable is set to true.

       -I, --include PATH
              specify  $LOAD_PATH.   PATH will be prepended to $LOAD_PATH.  The ':' character may
              be used to delimit multiple directories.  This directive  may  be  used  more  than
              once.   Modifications  to  $LOAD_PATH  take place immediately and in the order they
              were specified on the command-line.

       -r, --require LIBRARY
              require a specified  LIBRARY  before  executing  the  application.   The  "require"
              statement  will be executed immediately and in the order they were specified on the


       The following UNIX signals may be sent to the master process:

       · HUP - reload config file, app, and gracefully restart all workers

       · INT/TERM - quick shutdown, kills all workers immediately

       · QUIT - graceful shutdown, waits for workers  to  finish  their  current  request  before

       · USR1 - reopen all logs owned by the master and all workers See Unicorn::Util.reopen_logs
         for what is considered a log.

       · USR2 - reexecute the running binary.  A separate QUIT should be  sent  to  the  original
         process once the child is verified to be up and running.

       · WINCH  -  gracefully stops workers but keep the master running.  This will only work for
         daemonized processes.

       · TTIN - increment the number of worker processes by one

       · TTOU - decrement the number of worker processes by one

       See the SIGNALS ( document for full  description
       of all signals used by Unicorn.


       Accepted  values  of  RACK_ENV  and  the  middleware  they  automatically load (outside of
       RACKUP_FILE) are exactly as those in rackup(1):

       · development - loads Rack::CommonLogger, Rack::ShowExceptions, and Rack::Lint middleware

       · deployment - loads Rack::CommonLogger middleware

       · none - loads no middleware at all, relying entirely on RACKUP_FILE

       All unrecognized values for RACK_ENV are assumed to be "none".  Production deployments are
       strongly encouraged to use "deployment" or "none" for maximum performance.

       As of Unicorn 0.94.0, RACK_ENV is exported as a process-wide environment variable as well.
       While not current a part of the Rack specification as of Rack 1.0.1, this has become a  de
       facto standard in the Rack world.

       Note the Rack::ContentLength and Rack::Chunked middlewares are also loaded by "deployment"
       and "development", but no other values of RACK_ENV.  If needed, they must be  individually
       specified in the RACKUP_FILE, some frameworks do not require them.


       The  RACK_ENV  variable  is  set  by  the  aforementioned  -E  switch.  All application or
       library-specific environment variables (e.g.  TMPDIR) may always be  set  in  the  Unicorn
       CONFIG_FILE  in addition to the spawning shell.  When transparently upgrading Unicorn, all
       environment variables set in the old master  process  are  inherited  by  the  new  master
       process.   Unicorn  only  uses  (and  will  overwrite) the UNICORN_FD environment variable
       internally when doing transparent upgrades.

       UNICORN_FD is a comma-delimited list of one or more file  descriptors  used  to  implement
       USR2  upgrades.   Init  systems  may  bind  listen  sockets  itself and spawn unicorn with
       UNICORN_FD set to the file descriptor numbers of the listen socket(s).

       As of unicorn 5.0, LISTEN_PID and LISTEN_FDS are used for socket activation as  documented
       in  the  sd_listen_fds(3) manpage.  Users relying on this feature do not need to specify a
       listen socket in the unicorn config file.


       · Rack::Builder ri/RDoc

       · Unicorn::Configurator ri/RDoc

       · Unicorn RDoc (

       · Rack RDoc (

       · Rackup HowTo (


       The Unicorn Community <>.