WATCH(8) BSD System Manager's Manual WATCH(8)
watch -- snoop on another tty line
watch [-cinotW] [-f snpdev] [tty]
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 util-
ity 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.
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, inter-
active 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 ter-
-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
-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/.
While running in interactive mode, all user input is discarded except
Change attached tty, unless this feature is disabled, in which case
control-X is passed to the terminal as with other control charac-
pty(4), sio(4), snp(4), kldload(8)
No terminal emulation is performed. All user output is reproduced as-is.
Ugen J.S. Antsilevich <ugenATNetVision.il>
The watch utility first appeared in FreeBSD 2.1.
BSD November 24, 2001 BSD