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 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. 36If 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. 65This disables 66both change requests made with <control-X> as well as automatic prompting 67when the current tty is closed or overflows. 68In all cases where a prompt 69would be displayed, 70.Nm 71will exit. 72The reconnect flags are unaffected by 73this option. 74When this flag is used, <control-X> is passed through to the terminal. 75.It Fl o 76Reconnect on overflow. 77The behavior of 78.Nm 79if the observed tty overflows is similar to the behavior if the observed tty 80is closed. 81For more info see 82.Xr snp 4 . 83.It Fl t 84Print the date and time when observation of a given tty is started. 85.It Fl W 86Allow write access to observed tty. 87.It Ar tty 88Tty may be specified as a tty-style device, such as a pseudo tty device, 89a virtual console, or a serial line, etc. 90Names may be preceded by 91.Pa /dev/ . 92.El 93.Sh OPERATION 94While running in interactive mode, all user input is discarded except for: 95.Pp 96.Bl -tag -width "XXXX" -compact 97.It Sy "<control-G>" 98Exit 99.Nm . 100.It Sy "<control-W>" 101Clear screen. 102.It Sy "<control-X>" 103Change attached tty, unless this feature is disabled, in which case 104control-X is passed to the terminal as with other control characters. 105.El 106.Sh SEE ALSO 107.Xr pty 4 , 108.Xr sio 4 , 109.Xr snp 4 , 110.Xr kldload 8 111.Sh HISTORY 112The 113.Nm 114utility first appeared in 115.Fx 2.1 . 116.Sh AUTHORS 117.An Ugen J.S. Antsilevich Aq Mt ugen@NetVision.net.il 118.Sh BUGS 119No terminal emulation is performed. 120All user output is reproduced as-is. 121