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  avail-
     able,  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, au-
		tomatically 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 option.

     -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  over-
		flows.	 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 ports 15.1		November 24, 2001			WATCH(8)

Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=watch&sektion=8&manpath=FreeBSD+15.1-RELEASE+and+Ports>

home | help