diff --git a/tests/tester.sh b/tests/tester.sh
new file mode 100755
index 0000000..bb49609
--- /dev/null
+++ b/tests/tester.sh
@@ -0,0 +1,104 @@
+#!/bin/bash
+#
+# tester.sh - reads testcases from file and tests busybox applets vs GNU
+# counterparts
+#
+
+# set up defaults (can be changed with cmd-line options)
+BUSYBOX=../busybox
+TESTCASES=testcases
+LOGFILE=tester.log
+BB_OUT=bb.out
+GNU_OUT=gnu.out
+SETUP=""
+CLEANUP=""
+
+# internal-use vars
+fail_only=0
+
+
+while getopts 'p:t:l:b:g:s:c:f' opt
+do
+	case $opt in
+		p) BUSYBOX=$OPTARG; ;;
+		t) TESTCASES=$OPTARG; ;;
+		l) LOGFILE=$OPTARG; ;;
+		b) BB_OUT=$OPTARG; ;;
+		g) GNU_OUT=$OPTARG; ;;
+		s) SETUP=$OPTARG; ;;
+		c) CLEANUP=$OPTARG; ;;
+		f) fail_only=1; ;;
+		*)
+			echo "usage: $0 [-ptlbgsc]"
+			echo "  -p PATH  path to busybox executable"
+			echo "  -t FILE  run testcases in FILE"
+			echo "  -l FILE  log test results in FILE"
+			echo "  -b FILE  store temporary busybox output in FILE"
+			echo "  -g FILE  store temporary GNU output in FILE"
+			echo "  -s FILE  (setup) run commands in FILE before testcases"
+			echo "  -c FILE  (cleanup) run commands in FILE after testcases"
+			echo "  -f       display only testcases that fail"
+			exit 1
+			;;
+	esac
+done
+#shift `expr $OPTIND - 1`
+
+
+# do normal setup
+[ -e $LOGFILE ] && rm $LOGFILE
+unalias -a	# gets rid of aliases that might create different output
+
+# do extra setup (if any)
+if [ ! -z $SETUP ] 
+then
+	echo "running setup commands in $SETUP"
+	sh $SETUP
+	# XXX: Would 'eval' or 'source' work better instead of 'sh'?
+fi
+
+
+# go through each line in the testcase file
+cat $TESTCASES | while read line
+do
+	#echo $line
+	# only process non-blank lines and non-comment lines
+	if [ "$line" ]
+	then
+		if [ `echo "$line" | cut -c1` != "#" ]
+		then
+			[ $fail_only -eq 0 ] && echo "testing: $line" | tee -a $LOGFILE
+
+			# test if the applet was compiled into busybox
+			applet=`echo $line | cut -d' ' -f1`
+			$BUSYBOX 2>&1 | grep -qw $applet
+			if [ $? -eq 1 ]
+			then
+				echo "WHOOPS: $applet not compiled into busybox" | tee -a $LOGFILE
+			else
+				$BUSYBOX $line > $BB_OUT
+				$line > $GNU_OUT
+				diff -q $BB_OUT $GNU_OUT > /dev/null
+				if [ $? -eq 1 ]
+				then
+					echo "FAILED: $line" | tee -a $LOGFILE
+					diff -u $BB_OUT $GNU_OUT >> $LOGFILE 
+				fi
+			fi
+		fi
+	fi
+done
+
+echo "Finished. Results are in $LOGFILE"
+
+
+# do normal cleanup
+rm -f $BB_OUT $GNU_OUT
+
+# do extra cleanup (if any)
+if [ ! -z $CLEANUP ] 
+then
+	echo "running cleanup commands in $CLEANUP"
+	sh $CLEANUP
+	# XXX: Would 'eval' or 'source' work better instead of 'sh'?
+fi