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