WATCH(8)                FreeBSD 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
                interactive 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, interactive 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
                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 15.1-STABLE-HBSD       November 24, 2001                      WATCH(8)