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 op
- tion 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 de
- fault 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 inter
- actively.
- This disables both change requests made with <con
- trol-X> as well
as automatic prompting when the current tty is - closed or overflows. In all cases where a prompt would be dis
- played, 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 dis
- carded 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 con - trol characters.
SEE ALSO
pty(4), sio(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 re
- produced as-is.
- BSD November 24, 2001