1.\" 2.\" $FreeBSD$ 3.\" 4.Dd November 24, 2001 5.Dt WATCH 8 6.Os 7.Sh NAME 8.Nm watch 9.Nd snoop on another tty line 10.Sh SYNOPSIS 11.Nm 12.Op Fl cinotW 13.Op Fl f Ar snpdev 14.Op Ar tty 15.Sh DESCRIPTION 16.Nm Watch 17allows the user to examine all data coming through a specified tty 18using the 19.Xr snp 4 20device. 21If the 22.Xr snp 4 23device is not available, 24.Nm 25will attempt to load the module 26.Pq Nm snp . 27.Nm Watch 28writes to standard output. 29.Pp 30The options are as follows: 31.Bl -tag -width indent 32.It Fl c 33Reconnect on close. If the tty observed by 34.Nm 35is closed, automatically reattach to the same tty. 36If this option is not specified, 37.Nm 38will request a new tty if running in interactive mode or exit if running 39without a controlling tty. 40.It Fl f Ar snpdev 41If this option is specified, 42.Nm 43will use 44.Ar snpdev 45as the 46.Xr snp 4 47device. 48Without this option, 49.Nm 50will attempt to find the next available 51.Xr snp 4 52device. 53.It Fl i 54Force interactive mode. 55Interactive mode is a default if 56.Nm 57is started from a tty. 58If output is redirected to a file, interactive mode can still be requested 59by specifying this option. 60.It Fl n 61Disable the ability to switch the watched tty interactively. This disables 62both change requests made with <control-X> as well as automatic prompting 63when the current tty is closed or overflows. In all cases where a prompt 64would be displayed, 65.Nm 66will exit. The reconnect flags are unaffected by 67this option. 68When this flag is used, <control-X> is passed through to the terminal. 69.It Fl o 70Reconnect on overflow. 71The behavior of 72.Nm 73if the observed tty overflows is similar to the behavior if the observed tty 74is closed. 75For more info see 76.Xr snp 4 . 77.It Fl t 78Print the date and time when observation of a given tty is started. 79.It Fl W 80Allow write access to observed tty. 81.It Ar tty 82Tty may be specified as an tty-style device, such as a pseudo tty device, 83a virtual console, or a serial line, etc. 84Names may be preceded by 85.Pa /dev/ . 86.El 87.Sh OPERATION 88While running in interactive mode, all user input is discarded except for: 89.Pp 90.Bl -tag -width "XXXX" -compact 91.It Sy "<control-G>" 92Exit 93.Nm . 94.It Sy "<control-W>" 95Clear screen. 96.It Sy "<control-X>" 97Change attached tty, unless this feature is disabled, in which case 98control-X is passed to the terminal as with other control characters. 99.El 100.Sh SEE ALSO 101.Xr pty 4 , 102.Xr sio 4 , 103.Xr snp 4 , 104.Xr kldload 8 105.Sh BUGS 106No terminal emulation is performed. 107All user output is reproduced as-is. 108.Sh AUTHORS 109.An Ugen J.S. Antsilevich Aq ugen@NetVision.net.il 110.Sh HISTORY 111.Nm Watch 112first appeared in 113.Fx 2.1 . 114