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 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.
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
-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 characters.
pty(4), sio(4), snp(4), kldload(8)
No terminal emulation is performed. All user output is reproduced as-is.
Ugen J.S. Antsilevich <ugen@NetVision.net.il>
The watch utility first appeared in FreeBSD 2.1.
FreeBSD 5.2.1 November 24, 2001 FreeBSD 5.2.1 [ Back ]