Provided by: orville-write_2.55-2.3_amd64 bug

NAME

       mesg - permit or deny messages

SYNOPSIS

       mesg  [-s] [-v] [y|n|ye|ne|Y|N|NE] [d] [-p[w|t|k|a]] [-x[w|t|k|n]] [-m[l|c|a]] [-h[Y|y|n]]
       [-r[y|n]] [-b[y|n]]

DESCRIPTION

       This is the "Orville write" verison of the standard Unix mesg command.

       Mesg with argument n forbids messages  via  write(1),  ojot(1),  tel(1),  and  talk(1)  by
       revoking  non-user  write  permission  on  the  user's  terminal.   Mesg  with  argument y
       reinstates permission.  All by itself, mesg reports the current state without changing it.

       The  ne  and  ye  settings  mean  ``no  with  exceptions''  and  ``yes  with  exceptions''
       respectively.   If  ne  is  set, and there is file named .yeswrite in your home directory,
       then the users whose logins are listed there may still write you.  If ye is set, and there
       is  a  file  named .nowrite in your home directory, then the users whose logins are listed
       there may not write you.  These files have no effect if the permissions are set to n or y.
       The  .nowrite  and  .yeswrite files do not need to be permitted to anyone else, and almost
       any plausible format will be understood (listing  one  login  name  per  line  is  a  good
       default).  Lines may be commented out with a # sign in the first column.

       The  upper  case  Y and N do all that the lower case ones do, but may have some additional
       affects depending on the installation.

       The N argument, if enabled, will  attempt  to  disconnect  any  write  sessions  currently
       directed at your tty.  This is meant to allow users to slam the door on unwelcome writers.
       Note that a simple ``mesg n'' will not  stop  anyone  who  is  already  writing  you  from
       continuing  to  do  so,  it only prevents new connections from being made.  The NE setting
       also causes a disconnect, but turns your settings to ne instead  of  n.   The  d  argument
       causes a disconnect, just like ``mesg N'', but does not change your message permissions.

       Normally  mesg  always depermits your tty device, so you can only be written through write
       and similar programs.  This prevents arbitrary stuff from being redirected  to  your  tty.
       When you do ``mesg Y'' your tty is write permitted to others.  This is rarely necessary or
       desirable.

       Mesg can also be used to set other switches that affect Orville  write(1).   The  -p  flag
       lets  you  set preferences to (w) write, (t) telegrams, (k) talk, or (a) any.  The default
       is ``any.''  If you set a preference to write, then  people  will  not  be  able  to  send
       telegrams  or  talk requests to you.  If they try to send telegrams, they will be asked if
       they want to write you instead.  Similarly if you prefer telegrams,  people  will  not  be
       able  to write or talk to you, and if you prefer talk, people will not be able to write or
       tel you.  You can designate two preferences, like ``mesg -pt  -pw''  to  allow  people  to
       write or telegram you, but not make talk requests to you.  Alternately, you can use the -x
       flag to block particular programs.  Doing ``mesg -xk'' blocks only the talk  program,  and
       is equivalent to ``mesg -pt -pw''.  Similarly the ``-xn'' flag excludes no programs and is
       equivalent to ``-pa''.  Trying to block all programs just turns you permissions off.

       The -m flag lets you set modes to (l) line, (c) character, or (a)  any.   The  default  is
       ``any.''   If  you  set  a mode, then all writes to you will be done in that mode.  If you
       leave it as ``any,'' the choice is left to the writer.  This will not  affect  connections
       already in progress, only future ones.

       The  -r  flag  lets  you  turn on or off the recording to telegrams sent to you.  If it is
       enabled, everytime you are sent a telegram (or a write with input taken from a file),  the
       text  of  the  messages  is  saved in a file named .lastmesg in your home directory.  This
       allows you to redisplay the last message sent to you  using  the  huh(1)  command.   If  a
       screen  clear  ate a telegram message before you had time to read it, then the huh command
       lets you see it again.  Note that only the last message  sent  is  stored.   The  file  is
       permitted to be readable to you only.

       The -b flag lets you tell the write and talk programs whether or not to beep when a person
       writes you or sends you a telegram.  The default is to beep.

       The -h flag lets you turn on or off your helper status.  People who  designate  themselves
       as  helpers  are announcing their willingness to help out lost users.  Their accounts will
       be marked on the output of the finger(1) command, and if anyone does a write or ojot(1) to
       ``help''  they  automatically get connected to someone who has a help flag set.  Normally,
       turning your permissions off also turns your helper-status off, but if you set the -h flag
       to  Y,  then  you  will  remain a helper even when your message permissions are off.  This
       means you can receive help requests, but not normal messages.

       On some systems there is a restricted list of users who may be helpers.  This  is  usually
       kept  in  the  file /etc/helpers, one login name per line.  If such a file exists then you
       will have to get the operators to add your name to it to be able to designate yourself  as
       a helper.

       If  no  new  settings  are  given  to  mesg, then it just reports on the current settings.
       Normally it prints the message permissions, but if a -h, -p, -r,  or  -m  flag  was  given
       without  a  new  value  after  it,  then the current status of that switch will be printed
       instead.  If you use the -s flag, then this output will be suppressed.  The command  still
       reports the status of the selected switch with its numeric return code.

       If you use the -v flag, all switch settings will be reported in a verbose mode.

       The  numeric values returned as return codes (see below) can also be used to set switches.
       Thus ``mesg 0 -m2'' sets permissions on, and the mode to any.   This  makes  it  easy  for
       shell scripts to restore settings that were stored previously.

       The  argument  syntax  is  actually  a lot looser than mentioned above.  The dashes before
       options may be omitted, Spaces may be added or omitted anywhere in the argument list.

FILES

       /dev/tty*
       /etc/wrttmp
       /etc/helpers

SEE ALSO

       write(1), amin(1), finger(1), huh(1), helpers(1), talk(1)

DIAGNOSTICS

       Exit status is -1 on an error.  Otherwise a code is returned reporting the status  of  one
       of  the settings.  If the arguments included -h, -p, or -m flags without a new value after
       it, then the last of these listed will be reported.  Otherwise, if any options  were  set,
       the  last  of those listed in the argument list will be reported.  And if nothing was set,
       then message permissions are reported.

       When message permissions, record settings, or helper settings are  reported,  0  indicates
       'y',  and  1  indicates  'n'.  When preferences are reported, 1 indicates 'w', 2 indicates
       't', and 4 indicates 'k', and any combinations are returned as sums of these values.  When
       modes are reported, 0 indicates 'l', 1 indicates 'c', and 2 indicates 'a'.

BUGS

       Turning  off 'talk' permissions will only work if you have a talkd which has been modified
       to understand Orville write's permission.