Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
WATCH(8)		    System Manager's Manual		      WATCH(8)

NAME
       watch --	snoop on another tty line

SYNOPSIS
       watch [-cinotW] [-f snpdev] [tty]

DESCRIPTION
       The  watch utility allows the user to examine all data coming through a
       specified tty using the snp(4) device.  If the  snp(4)  device  is  not
       available,  watch  will	attempt	 to  load the module (snp).  The watch
       utility writes to standard output.

       The options are as follows:

       -c      Reconnect on close.  If the tty observed	by  watch  is  closed,
	       automatically  reattach to the same tty.	 If this option	is not
	       specified, watch	will request a new tty if running in  interac-
	       tive mode or exit if running without a controlling tty.

       -f snpdev
	       If  this	 option	 is  specified,	 watch	will use snpdev	as the
	       snp(4) device.  Without this option, watch will attempt to find
	       the next	available snp(4) device.

       -i      Force interactive mode.	Interactive mode is a default if watch
	       is started from a tty.  If output is redirected to a file,  in-
	       teractive  mode	can  still be requested	by specifying this op-
	       tion.

       -n      Disable the ability to switch the  watched  tty	interactively.
	       This  disables  both  change  requests made with	<control-X> as
	       well as automatic prompting when	the current tty	is  closed  or
	       overflows.   In	all  cases  where a prompt would be displayed,
	       watch will exit.	 The reconnect flags are  unaffected  by  this
	       option.	 When this flag	is used, <control-X> is	passed through
	       to the terminal.

       -o      Reconnect on overflow.  The behavior of watch if	 the  observed
	       tty overflows is	similar	to the behavior	if the observed	tty is
	       closed.	For more info see snp(4).

       -t      Print  the  date	 and  time  when observation of	a given	tty is
	       started.

       -W      Allow write access to observed tty.

       tty     Tty may be specified as a tty-style device, such	 as  a	pseudo
	       tty  device,  a	virtual	console, or a serial line, etc.	 Names
	       may be preceded by /dev/.

OPERATION
       While running in	interactive mode, all user input is  discarded	except
       for:

       <control-G>
	     Exit watch.
       <control-W>
	     Clear screen.
       <control-X>
	     Change  attached  tty,  unless this feature is disabled, in which
	     case control-X is passed to the terminal as  with	other  control
	     characters.

SEE ALSO
       pty(4), snp(4), kldload(8)

HISTORY
       The watch utility first appeared	in FreeBSD 2.1.

AUTHORS
       Ugen J.S. Antsilevich <ugen@NetVision.net.il>

BUGS
       No  terminal emulation is performed.  All user output is	reproduced as-
       is.

FreeBSD	13.2		       November	24, 2001		      WATCH(8)

NAME | SYNOPSIS | DESCRIPTION | OPERATION | SEE ALSO | HISTORY | AUTHORS | BUGS

Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=watch&manpath=FreeBSD+14.1-RELEASE+and+Ports>

home | help