.SH SYNOPSIS
.B ykchalresp
[\fI-1\fR | \fI-2\fR] [\fI-H\fR] [\fI-Y\fR] [\fI-N\fR] [\fI-x\fR] [\fI-v\fR] [\fI-h\fR]
-.\".SH DESCRIPTION
-.\" Add any additional description here
-.SH OPTIONS
+.SH DESCRIPTION
.PP
Send a challenge to a YubiKey, and read the response. The YubiKey can be configured
with two different C/R modes -- the standard one is a 160 bits HMAC-SHA1, and the other
is a YubiKey OTP mimicing mode, meaning two subsequent calls with the same challenge
will result in different responses.
+.SH OPTIONS
.TP
\fB\-1\fR
send the challenge to slot 1. This is the default.