Provided by: gnuserv_3.12.8-7_amd64 bug


       gnuserv, gnuclient - Server and Clients for Emacs and XEmacs


       gnuclient  [-display  display]  [-q] [-v] [-l library] [-batch] [-f function] [-eval form]
       [-h hostname] [-p port] [-r remote-pathname] [[+line] file] ...
       gnudoit [-q] form
       gnuattach Removed as of gnuserv 3.x


       gnuclient allows the user to request a running Emacs or XEmacs process to edit  the  named
       files or directories and/or evaluate lisp forms.  Depending on your environment, it can be
       an X frame or a TTY frame.  One typical use for this is with  a  dialup  connection  to  a
       machine on which an Emacs or XEmacs process is currently running.

       gnudoit  is  a  shell  script  frontend  to  ``gnuclient  -batch -eval form''.  Its use is
       deprecated. Try to get used to calling gnuclient directly.

       gnuserv is the server program that is set  running  by  Emacs  or  XEmacs  to  handle  all
       incoming  and  outgoing  requests. It is not usually invoked directly, but is started from
       Emacs or XEmacs by loading the gnuserv package and  evaluating  the  Lisp  form  (gnuserv-

       gnuattach no longer exists.


       gnuclient  supports  as  much  of the command line options of Emacs as makes sense in this
       context. In addition it adds a few of its own.
       Options with long names can also be specified using a double hyphen instead  of  a  single

       -display display, --display display
               If  this  option  is  given  or  the  `DISPLAY'  environment  variable is set then
               gnuclient will tell Emacs to edit files in a frame on the specified X device.

       -q      This option informs gnuclient to exit once  connection  has  been  made  with  the
               XEmacs  process.   Normally  gnuclient waits until all of the files on the command
               line have been finished with (their buffers killed) by the XEmacs process, and all
               the forms have been evaluated.

       -v      When this option is specified gnuclient will request for the specified files to be
               viewed instead of edited.

       -l library
               Tell Emacs to load the specified library.

       -batch  Tell Emacs not to open any frames. Just load libraries and evaluate lisp code.  If
               no  files  to  execute, functions to call or forms to eval are given using the -l,
               -f, or -eval options, then forms to eval are read from STDIN.

       -f function,
               Make Emacs execute the lisp function.

       -eval form
               Make Emacs execute the lisp form.

       -h hostname
               Used only with Internet-domain sockets, this option  specifies  the  host  machine
               which should be running gnuserv. If this option is not specified then the value of
               the environment variable GNU_HOST is used if set. If no hostname is specified, and
               the  GNU_HOST  variable  is not set, an internet connection will not be attempted.
               N.B.: gnuserv does NOT allow internet connections unless XAUTH  authentication  is
               used  or  the  GNU_SECURE variable has been specified and points at a file listing
               all trusted hosts. (See SECURITY below.)

               Note that an internet address may be specified instead of  a  hostname  which  can
               speed  up  connections  to  the  server  by  quite a bit, especially if the client
               machine is running YP.

               Note also that a hostname of unix can be used to specify that  the  connection  to
               the server should use a Unix-domain socket (if supported) rather than an Internet-
               domain socket.

       -p port Used only with Internet-domain sockets, this option  specifies  the  service  port
               used  to communicate between server and clients.  If this option is not specified,
               then the value of the environment variable GNU_PORT is used, if set,  otherwise  a
               service  called ``gnuserv'' is looked up in the services database.  Finally, if no
               other value can be found for the port, then  a  default  port  is  used  which  is
               usually 21490 + uid.
               Note  that  since gnuserv doesn't allow command-line options, the port for it will
               have to be specified via one of the alternative methods.

       -r pathname
               Used only with Internet-domain sockets, the pathname argument  may  be  needed  to
               inform  Emacs  how  to  reach  the  root directory of a remote machine.  gnuclient
               prepends this string to each path argument given.  For example, if you were trying
               to  edit  a  file  on  a  client  machine  called  otter, whose root directory was
               accessible from the server machine via the path  /net/otter,  then  this  argument
               should be set to '/net/otter'.  If this option is omitted, then the value is taken
               from the environment variable GNU_NODE, if set, or the empty string otherwise.

       [+n] file
               This is the path of the file to be edited.  If the file is a directory,  then  the
               directory browsers dired or monkey are usually invoked instead.  The cursor is put
               at line number 'n' if specified.


       gnuserv is packaged standardly with recent versions of XEmacs.  Therefore, you  should  be
       able  to  start  the  server simply by evaluating the XEmacs Lisp form (gnuserv-start), or
       equivalently by typing `M-x gnuserv-start'.


       The behavior of this suite of program is mostly controlled on the lisp side in  Emacs  and
       its  behavior  can be customized to a large extent.  Type `M-x customize-group RET gnuserv
       RET' for easy access. More documentation can be found in the file `gnuserv.el'


           gnuclient -q -f mh-smail
           gnuclient -h cuckoo -r /ange@otter: /tmp/*
           gnuclient ../src/listproc.c

       More examples and sample wrapper scripts are provided in the etc/gnuserv directory of  the
       Emacs installation.


       SysV  IPC  is  used to communicate between gnuclient and gnuserv if the symbol SYSV_IPC is
       defined at the top of gnuserv.h. This is incompatible with both Unix-domain and  Internet-
       domain socket communication as described below. A file called /tmp/gsrv??? is created as a
       key for the message queue, and if removed will cause the communication between server  and
       client to fail until the server is restarted.


       A  Unix-domain  socket  is used to communicate between gnuclient and gnuserv if the symbol
       UNIX_DOMAIN_SOCKETS   is   defined   at   the   top   of   gnuserv.h.    A   file   called
       /tmp/gsrvdir????/gsrv  is  created  for communication.  If the symbol USE_TMPDIR is set at
       the top of gnuserv.h, $TMPDIR, when set, is  used  instead  of  /tmp.   If  that  file  is
       deleted,  or  TMPDIR  has  different  values  for the server and the client, communication
       between server and client will fail.  Only the  user  running  gnuserv  will  be  able  to
       connect to the socket.


       Internet-domain  sockets  are  used  to  communicate  between gnuclient and gnuserv if the
       symbol INTERNET_DOMAIN_SOCKETS is defined at the top of  gnuserv.h.  Both  Internet-domain
       and Unix-domain sockets can be used at the same time. If a hostname is specified via -h or
       via the GNU_HOST environment variable, gnuclient establish connections using  an  internet
       domain  socket. If not, a local connection is attempted via either a unix-domain socket or
       SYSV IPC.


       Using Internet-domain sockets, a more robust  form  of  security  is  needed  that  wasn't
       necessary  with  either  Unix-domain  sockets  or  SysV IPC. Currently, two authentication
       protocols are supported to provide this: MIT-MAGIC-COOKIE-1 (based  on  the  X11  xauth(1)
       program) and a simple host-based access control mechanism, hereafter called GNUSERV-1. The
       GNUSERV-1 protocol is always available, whereas support for MIT-MAGIC-COOKIE-1 may or  may
       not have been enabled (via a #define at the top of gnuserv.h) at compile-time.

       gnuserv,  using GNUSERV-1, performs a limited form of access control at the machine level.
       By default no internet-domain socket is opened.  If the variable GNU_SECURE can  be  found
       in  gnuserv's  environment, and it names a readable filename, then this file is opened and
       assumed to be a list of hosts, one per line, from which the server  will  allow  requests.
       Connections  from  any  other  host will be rejected. Even the machine on which gnuserv is
       running is not permitted to make connections via the internet socket unless  its  hostname
       is explicitly specified in this file.  Note that a host may be either a numeric IP address
       or a hostname, and that any user on an approved host  may  connect  to  your  gnuserv  and
       execute  arbitrary  elisp  (e.g.,  delete all your files).  If this file contains a lot of
       hostnames then the server may take quite a time to start up.

       When the MIT-MAGIC-COOKIE-1 protocol is enabled, an internet socket is opened by  default.
       gnuserv  will  accept  a  connection  from  any  host,  and will wait for a "magic cookie"
       (essentially, a password) to be presented by the client. If the client doesn't present the
       cookie,  or if the cookie is wrong, the authentication of the client is considered to have
       failed. At this point. gnuserv falls back to the GNUSERV-1  protocol;  If  the  client  is
       calling  from  a  host  listed  in  the  GNU_SECURE file, the connection will be accepted,
       otherwise it will be rejected.

       Using MIT-MAGIC-COOKIE-1 authentication
           When the gnuserv server is started, it looks for a cookie defined for display  999  on
           the  machine where it is running. If the cookie is found, it will be stored for use as
           the authentication cookie. These cookies are defined in an authorization file (usually
           ~/.Xauthority) that is manipulated by the X11 xauth(1) program. For example, a machine
           "kali" which runs an emacs that invokes gnuserv should  respond  as  follows  (at  the
           shell prompt) when set up correctly.

               kali% xauth list
               GS65.SP.CS.CMU.EDU:0  MIT-MAGIC-COOKIE-1  11223344
               KALI.FTM.CS.CMU.EDU:999  MIT-MAGIC-COOKIE-1  1234

           In the above case, the authorization file defines two cookies. The second one, defined
           for screen 999 on the server machine, is used for gnuserv authentication.

           On the client machine's side, the authorization file must contain an  identical  line,
           specifying  the server's cookie. In other words, on a machine "foobar" which wishes to
           connect to "kali,"  the `xauth list' output should contain the line:

               KALI.FTM.CS.CMU.EDU:999  MIT-MAGIC-COOKIE-1  1234

           To create the cookie, you can use a command like
               xauth add `hostname`:999 MIT-MAGIC-COOKIE-1 `head -c512 /dev/urandom|md5sum`

           For more information on authorization files, take a look at the xauth(1X11) man  page,
           or  invoke  xauth interactively (without any arguments) and type "help" at the prompt.
           Remember that  case  in  the  name  of  the  authorization  protocol  (i.e.`MIT-MAGIC-
           COOKIE-1') is significant!


       DISPLAY Default X device to put edit frame.


               (SYSV_IPC only)

               (unix domain sockets only)

               Emacs customization file, see emacs(1) and xemacs(1).


       dtemacs(1), xauth(1X11), Xsecurity(1X11), gnuserv.el


       NULs occurring in result strings don't get passed back to gnudoit properly.


       Andy Norman (, based heavily upon etc/emacsclient.c, etc/server.c and
       lisp/server.el from the GNU Emacs 18.52  distribution.   Various  modifications  from  Bob
       Weiner    (,    Darrell    Kindred   (,   Arup   Mukherjee
       (, Ben Wing ( and Hrvoje Niksic (