X-Git-Url: http://club.cc.cmu.edu/~cmccabe/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=mbr_dump.sh;h=d97e450353b57cdf163d81f973563ae21d2d7a1a;hb=ef32118a10785fe6792d3bad1d4b11590460bffe;hp=dce79628d02b307e4847971a7dbe9613b015eabf;hpb=e915a0738a5e314ed9282674f8bbc07325388d5a;p=cmccabe-bin

diff --git a/mbr_dump.sh b/mbr_dump.sh
index dce7962..d97e450 100755
--- a/mbr_dump.sh
+++ b/mbr_dump.sh
@@ -6,14 +6,22 @@
 #
 # Colin McCabe
 #
+usage() {
+	echo "usage: ${0} <IBM-master-boot-record>"
+	echo "should be 512 bytes in length."
+	exit 1
+}
+
+if [ $# -ne 1 ]; then
+	usage
+fi
 
 if [ -e ${1} ]; then
 	PART_FILE=${1}
 else
-	echo "usage: ${0} <IBM-master-boot-record>"
-	echo "should be 512 bytes in length."
-	exit 1
+	usage
 fi
+
 echo "# first partition"
 od -j 446 -N 16 -t x1 ${1}
 echo "# second partition"