From: Colin Patrick McCabe <cmccabe@alumni.cmu.edu>
Date: Thu, 13 May 2010 03:54:49 +0000 (-0700)
Subject: mbr_dump.sh: should check script arguments better
X-Git-Url: http://club.cc.cmu.edu/~cmccabe/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=edb43243c72c55d5416254280ea9ee44cd9816ee;p=cmccabe-bin

mbr_dump.sh: should check script arguments better
---

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"