.TH ISUP 1 "August 2003" CSLib "CSLib Utilities"
.nh
.SH NAME
isup \- Find out if a machine is up by trying a TCP/IP connection
.SH SYNOPSIS
.B isup
[ \fB\-v\fP ] [ \fB\-a\fP ] [ \fB-t SECONDS\fP ] \fBhost\fP [ \fBport\fP ]
.SH DESCRIPTION
.B isup
tries to create a TCP/IP connection to \fBhost\fP (optionally on port 
\fBport\fP, default is TCP 7, i.e. echo). If the machine is up (i.e.
the connection is accepted, or refused), then zero (success) is returned.
A non-zero error code is returned if the connection fails.
.TP
\fB\-v\fP, \fB\-\-verbose\fP
Also print out an explanatory line of whether the machine is available
or not, and if not, what the error was.
.TP
\fB\-a\fP, \fB\-\-available\fP
Will only return success if a connection can actually be made on the
specified port - connection refused will return a non-zero error code.
.TP
\fB\-t\fP, \fB\-\-timeout=SECONDS\fP
This will set a custom timeout for testing, given in seconds. If not 
specified, the timeout will be down to the timeout in the system's 
connect(2) call.
.TP
\fB\-h\fP, \fB\-\-help\fP
Display usage information.
.SH AUTHOR
.B isup
was written by Alan Ford <ajf101@ecs.soton.ac.uk> <alan@whirlnet.co.uk>.
.SH SEE ALSO
.BR connect (2), 
.BR gethostbyname (3)