1.\" 2.\" $FreeBSD: src/usr.sbin/watch/watch.8,v 1.18.2.4 2003/03/11 22:31:34 trhodes Exp $ 3.\" $DragonFly: src/usr.sbin/watch/watch.8,v 1.2 2003/06/17 04:30:04 dillon Exp $ 4.\" 5.Dd November 24, 2001 6.Dt WATCH 8 7.Os 8.Sh NAME 9.Nm watch 10.Nd snoop on another tty line 11.Sh SYNOPSIS 12.Nm 13.Op Fl cinotW 14.Op Fl f Ar snpdev 15.Op Ar tty 16.Sh DESCRIPTION 17The 18.Nm 19utility allows the user to examine all data coming through a specified tty 20using the 21.Xr snp 4 22device. 23If the 24.Xr snp 4 25device is not available, 26.Nm 27will attempt to load the module 28.Pq Nm snp . 29The 30.Nm 31utility writes to standard output. 32.Pp 33The options are as follows: 34.Bl -tag -width indent 35.It Fl c 36Reconnect on close. If the tty observed by 37.Nm 38is closed, automatically reattach to the same tty. 39If this option is not specified, 40.Nm 41will request a new tty if running in interactive mode or exit if running 42without a controlling tty. 43.It Fl f Ar snpdev 44If this option is specified, 45.Nm 46will use 47.Ar snpdev 48as the 49.Xr snp 4 50device. 51Without this option, 52.Nm 53will attempt to find the next available 54.Xr snp 4 55device. 56.It Fl i 57Force interactive mode. 58Interactive mode is a default if 59.Nm 60is started from a tty. 61If output is redirected to a file, interactive mode can still be requested 62by specifying this option. 63.It Fl n 64Disable the ability to switch the watched tty interactively. This disables 65both change requests made with <control-X> as well as automatic prompting 66when the current tty is closed or overflows. In all cases where a prompt 67would be displayed, 68.Nm 69will exit. The reconnect flags are unaffected by 70this option. 71When this flag is used, <control-X> is passed through to the terminal. 72.It Fl o 73Reconnect on overflow. 74The behavior of 75.Nm 76if the observed tty overflows is similar to the behavior if the observed tty 77is closed. 78For more info see 79.Xr snp 4 . 80.It Fl t 81Print the date and time when observation of a given tty is started. 82.It Fl W 83Allow write access to observed tty. 84.It Ar tty 85Tty may be specified as a tty-style device, such as a pseudo tty device, 86a virtual console, or a serial line, etc. 87Names may be preceded by 88.Pa /dev/ . 89.El 90.Sh OPERATION 91While running in interactive mode, all user input is discarded except for: 92.Pp 93.Bl -tag -width "XXXX" -compact 94.It Sy "<control-G>" 95Exit 96.Nm . 97.It Sy "<control-W>" 98Clear screen. 99.It Sy "<control-X>" 100Change attached tty, unless this feature is disabled, in which case 101control-X is passed to the terminal as with other control characters. 102.El 103.Sh SEE ALSO 104.Xr pty 4 , 105.Xr sio 4 , 106.Xr snp 4 , 107.Xr kldload 8 108.Sh BUGS 109No terminal emulation is performed. 110All user output is reproduced as-is. 111.Sh AUTHORS 112.An Ugen J.S. Antsilevich Aq ugen@NetVision.net.il 113.Sh HISTORY 114The 115.Nm 116utility first appeared in 117.Fx 2.1 . 118