1995d3a484
Previously, watch would always use the first device it could successfully open, but this isn't always desired. Specifically, it may not be desired during debugging (of snp), or if a particular snp device has different permissions (which makes since after snp.c 1.64).
109 lines
2.5 KiB
Groff
109 lines
2.5 KiB
Groff
.\"
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.\" @(#)watch.8 1.1 (FreeBSD) 2/17/95
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.\" $FreeBSD$
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.\"
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.Dd November 24, 2001
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.Dt WATCH 8
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.Os
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.Sh NAME
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.Nm watch
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.Nd snoop on another tty line
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.Sh SYNOPSIS
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.Nm
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.Op Fl ciotnW
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.Op Fl f Ar snpdev
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.Op Ar tty
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.\" watch [-ciotnW] [<tty name>]
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.Sh DESCRIPTION
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.Nm Watch
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allows the superuser to examine all data coming through a specified tty.
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.Nm Watch
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writes to standard output.
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.Pp
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The options are as follows:
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.Bl -tag -width indent
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.It Fl c
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Reconnect on close. If the tty observed by
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.Nm
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is closed, automatically reattach to the same tty.
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If this option is not specified,
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.Nm
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will request a new tty if running in interactive mode or exit if running
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without a controlling tty.
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.It Fl f Ar snpdev
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If this option is specified,
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.Nm
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will use
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.Ar snpdev
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as the
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.Xr snp 4
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device.
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Without this option,
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.Nm
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will attempt to find the next available
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.Xr snp 4
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device.
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.It Fl i
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Force interactive mode.
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Interactive mode is a default if
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.Nm
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is started from a tty.
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If output is redirected to a file, interactive mode can still be requested
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by specifying this option.
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.It Fl o
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Reconnect on overflow.
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The behavior of
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.Nm
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if the observed tty overflows is similar to the behavior if the observed tty
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is closed.
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For more info see
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.Xr snp 4 .
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.It Fl t
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Print the date and time when observation of a given tty is started.
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.It Fl n
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Disable the ability to switch the watched tty interactively. This disables
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both change requests made with <control-X> as well as automatic prompting
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when the current tty is closed or overflows. In all cases where a prompt
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would be displayed,
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.Nm
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will exit. The reconnect flags are unaffected by
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this option.
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When this flag is used, <control-X> is passed through to the terminal.
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.It Fl W
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Allow write access to observed tty.
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.It Ar tty
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Tty may be specified as an tty-style device, such as a pseudo tty device,
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a virtual console, or a serial line, etc.
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Names may be preceded by
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.Pa /dev/ .
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.El
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.Sh OPERATION
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While running in interactive mode, all user input is discarded except for:
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.Pp
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.Bl -tag -width "XXXX" -compact
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.It Sy "<control-G>"
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Exit
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.Nm .
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.It Sy "<control-W>"
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Clear screen.
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.It Sy "<control-X>"
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Change attached tty, unless this feature is disabled, in which case
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control-X is passed to the terminal as with other control characters.
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.El
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.Sh RESTRICTIONS
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Only the superuser can run
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.Nm .
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.Sh SEE ALSO
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.Xr pty 4 ,
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.Xr sio 4 ,
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.Xr snp 4
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.Sh BUGS
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No terminal emulation is performed.
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All user output is reproduced as-is.
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.Sh AUTHORS
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.An Ugen J.S. Antsilevich Aq ugen@NetVision.net.il
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.Sh HISTORY
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.Nm Watch
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first appeared in
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.Fx 2.1 .
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