1.\" 2.\" $FreeBSD: src/usr.sbin/watch/watch.8,v 1.18.2.4 2003/03/11 22:31:34 trhodes Exp $ 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 16The 17.Nm 18utility allows the user to examine all data coming through a specified tty 19using the 20.Xr snp 4 21device. 22If the 23.Xr snp 4 24device is not available, 25.Nm 26will attempt to load the module 27.Pq Nm snp . 28The 29.Nm 30utility writes to standard output. 31.Pp 32The options are as follows: 33.Bl -tag -width indent 34.It Fl c 35Reconnect on close. If the tty observed by 36.Nm 37is closed, automatically reattach to the same tty. 38If this option is not specified, 39.Nm 40will request a new tty if running in interactive mode or exit if running 41without a controlling tty. 42.It Fl f Ar snpdev 43If this option is specified, 44.Nm 45will use 46.Ar snpdev 47as the 48.Xr snp 4 49device. 50Without this option, 51.Nm 52will attempt to find the next available 53.Xr snp 4 54device. 55.It Fl i 56Force interactive mode. 57Interactive mode is a default if 58.Nm 59is started from a tty. 60If output is redirected to a file, interactive mode can still be requested 61by specifying this option. 62.It Fl n 63Disable the ability to switch the watched tty interactively. This disables 64both change requests made with <control-X> as well as automatic prompting 65when the current tty is closed or overflows. In all cases where a prompt 66would be displayed, 67.Nm 68will exit. The reconnect flags are unaffected by 69this option. 70When this flag is used, <control-X> is passed through to the terminal. 71.It Fl o 72Reconnect on overflow. 73The behavior of 74.Nm 75if the observed tty overflows is similar to the behavior if the observed tty 76is closed. 77For more info see 78.Xr snp 4 . 79.It Fl t 80Print the date and time when observation of a given tty is started. 81.It Fl W 82Allow write access to observed tty. 83.It Ar tty 84Tty may be specified as a tty-style device, such as a pseudo tty device, 85a virtual console, or a serial line, etc. 86Names may be preceded by 87.Pa /dev/ . 88.El 89.Sh OPERATION 90While running in interactive mode, all user input is discarded except for: 91.Pp 92.Bl -tag -width "XXXX" -compact 93.It Sy "<control-G>" 94Exit 95.Nm . 96.It Sy "<control-W>" 97Clear screen. 98.It Sy "<control-X>" 99Change attached tty, unless this feature is disabled, in which case 100control-X is passed to the terminal as with other control characters. 101.El 102.Sh SEE ALSO 103.Xr pty 4 , 104.Xr sio 4 , 105.Xr snp 4 , 106.Xr kldload 8 107.Sh HISTORY 108The 109.Nm 110utility first appeared in 111.Fx 2.1 . 112.Sh AUTHORS 113.An Ugen J.S. Antsilevich Aq Mt ugen@NetVision.net.il 114.Sh BUGS 115No terminal emulation is performed. 116All user output is reproduced as-is. 117