--- ./lib/pdfopt	2002-04-23 14:58:36.000000000 +0300
+++ ./lib/pdfopt	2006-01-20 18:30:21.000000000 +0200
@@ -16,8 +16,9 @@
 	shift
 done
 
-if [ $# -ne 2 ]; then
-	echo "Usage: `basename $0` input.pdf output.pdf" 1>&2
+if [ $# -lt 2 ] || [ "$1" = "$2" ]; then
+	echo "Usage: `basename $0` [ gs options ] input.pdf output.pdf" 1>&2
+	echo "       (input.pdf must be different from output.pdf to avoid corruption)" 1>&2
 	exit 1
 fi
 
--- ./man/pdfopt.1	2003-07-13 07:43:17.000000000 +0300
+++ ./man/pdfopt.1	2006-01-20 18:40:36.000000000 +0200
@@ -13,7 +13,7 @@
 through a network.
 .PP
 Note: input.pdf and output.pdf must not be the same.  If they are, the file
-will probably be destroyed.  \fBpdfopt\fR currently does not check for this.
+will probably be destroyed. \fBpdfopt\fR checks for this.
 .SH FILES
 Run "\fBgs -h\fR" to find the location of Ghostscript documentation on your
 system, from which you can get more details.