--- a/dropbearkey.1	Fri Aug 07 21:26:03 2015 +0800
+++ b/dropbearkey.1	Mon Nov 23 23:04:48 2015 +0800
@@ -9,6 +9,7 @@
 .I file
 [\-s
 .IR bits ]
+[\-y]
 .SH DESCRIPTION
 .B dropbearkey
 generates a
@@ -39,12 +40,19 @@
 Set the key size to
 .I bits
 bits, should be multiple of 8 (optional). 
+.TP
+.B \-y
+Just print the publickey and fingerprint for the private key in \fIfile\fR.
 .SH NOTES
 The program dropbearconvert(1) can be used to convert between Dropbear and OpenSSH key formats.
 .P
 Dropbear does not support encrypted keys. 
 .SH EXAMPLE
+generate a host-key:
  # dropbearkey -t rsa -f /etc/dropbear/dropbear_rsa_host_key
+
+extract a public key suitable for authorized_keys from private key:
+ # dropbearkey -y -f id_rsa | grep "^ssh-rsa " >> authorized_keys
 .SH AUTHOR
 Matt Johnston ([email protected]).
 .br