diff --git a/src/Makefile b/src/Makefile
index d73f381b..89355984 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -55,7 +55,7 @@ endif
 
 FINAL_CFLAGS=$(STD) $(WARN) $(OPT) $(DEBUG) $(CFLAGS) $(REDIS_CFLAGS) -I../deps/geohash-int
 FINAL_LDFLAGS=$(LDFLAGS) $(REDIS_LDFLAGS) $(DEBUG)
-FINAL_LIBS=-lm -ldl
+FINAL_LIBS=-lm
 DEBUG=-g -ggdb
 
 ifeq ($(uname_S),SunOS)
@@ -65,17 +65,27 @@ ifeq ($(uname_S),SunOS)
 	FINAL_LIBS+= -ldl -lnsl -lsocket -lresolv -lpthread -lrt
 else
 ifeq ($(uname_S),Darwin)
-	# Darwin (nothing to do)
+	# Darwin
+	FINAL_LIBS+= -ldl
 else
 ifeq ($(uname_S),AIX)
         # AIX
         FINAL_LDFLAGS+= -Wl,-bexpall
-        FINAL_LIBS+= -pthread -lcrypt -lbsd
-
+        FINAL_LIBS+=-ldl -pthread -lcrypt -lbsd
+else
+ifeq ($(uname_S),OpenBSD)
+	# OpenBSD
+	FINAL_LIBS+= -lpthread
+else
+ifeq ($(uname_S),FreeBSD)
+	# FreeBSD
+	FINAL_LIBS+= -lpthread
 else
 	# All the other OSes (notably Linux)
 	FINAL_LDFLAGS+= -rdynamic
-	FINAL_LIBS+= -pthread
+	FINAL_LIBS+=-ldl -pthread
+endif
+endif
 endif
 endif
 endif
diff --git a/src/bitops.c b/src/bitops.c
index 699681bc..8d64f23e 100644
--- a/src/bitops.c
+++ b/src/bitops.c
@@ -775,6 +775,10 @@ void bitcountCommand(client *c) {
         /* Convert negative indexes */
         if (start < 0) start = strlen+start;
         if (end < 0) end = strlen+end;
+        if ((start < 0) && (end < 0) && (start > end)) {
+            addReply(c,shared.czero);
+            return;
+        }
         if (start < 0) start = 0;
         if (end < 0) end = 0;
         if (end >= strlen) end = strlen-1;
diff --git a/utils/install_server.sh b/utils/install_server.sh
index 98e047e3..3d920a12 100755
--- a/utils/install_server.sh
+++ b/utils/install_server.sh
@@ -25,9 +25,25 @@
 #
 ################################################################################
 #
-# Interactive service installer for redis server
-# this generates a redis config file and an /etc/init.d script, and installs them
-# this scripts should be run as root
+# Service installer for redis server, runs interactively by default.
+#
+# To run this script non-interactively (for automation/provisioning purposes),
+# feed the variables into the script. Any missing variables will be prompted!
+# Tip: Environment variables also support command substitution (see REDIS_EXECUTABLE)
+#
+# Example:
+#
+# sudo REDIS_PORT=1234 \
+# 		 REDIS_CONFIG_FILE=/etc/redis/1234.conf \
+# 		 REDIS_LOG_FILE=/var/log/redis_1234.log \
+# 		 REDIS_DATA_DIR=/var/lib/redis/1234 \
+# 		 REDIS_EXECUTABLE=`command -v redis-server` ./utils/install_server.sh
+#
+# This generates a redis config file and an /etc/init.d script, and installs them.
+#
+# /!\ This script should be run as root
+#
+################################################################################
 
 die () {
 	echo "ERROR: $1. Aborting!"
@@ -42,6 +58,7 @@ SCRIPTPATH=$(dirname $SCRIPT)
 
 #Initial defaults
 _REDIS_PORT=6379
+_MANUAL_EXECUTION=false
 
 echo "Welcome to the redis service installer"
 echo "This script will help you easily set up a running redis server"
@@ -53,47 +70,61 @@ if [ "$(id -u)" -ne 0 ] ; then
 	exit 1
 fi
 
-#Read the redis port
-read  -p "Please select the redis port for this instance: [$_REDIS_PORT] " REDIS_PORT
 if ! echo $REDIS_PORT | egrep -q '^[0-9]+$' ; then
-	echo "Selecting default: $_REDIS_PORT"
-	REDIS_PORT=$_REDIS_PORT
+	_MANUAL_EXECUTION=true
+	#Read the redis port
+	read  -p "Please select the redis port for this instance: [$_REDIS_PORT] " REDIS_PORT
+	if ! echo $REDIS_PORT | egrep -q '^[0-9]+$' ; then
+		echo "Selecting default: $_REDIS_PORT"
+		REDIS_PORT=$_REDIS_PORT
+	fi
 fi
 
-#read the redis config file
-_REDIS_CONFIG_FILE="/etc/redis/$REDIS_PORT.conf"
-read -p "Please select the redis config file name [$_REDIS_CONFIG_FILE] " REDIS_CONFIG_FILE
 if [ -z "$REDIS_CONFIG_FILE" ] ; then
-	REDIS_CONFIG_FILE=$_REDIS_CONFIG_FILE
-	echo "Selected default - $REDIS_CONFIG_FILE"
+	_MANUAL_EXECUTION=true
+	#read the redis config file
+	_REDIS_CONFIG_FILE="/etc/redis/$REDIS_PORT.conf"
+	read -p "Please select the redis config file name [$_REDIS_CONFIG_FILE] " REDIS_CONFIG_FILE
+	if [ -z "$REDIS_CONFIG_FILE" ] ; then
+		REDIS_CONFIG_FILE=$_REDIS_CONFIG_FILE
+		echo "Selected default - $REDIS_CONFIG_FILE"
+	fi
 fi
 
-#read the redis log file path
-_REDIS_LOG_FILE="/var/log/redis_$REDIS_PORT.log"
-read -p "Please select the redis log file name [$_REDIS_LOG_FILE] " REDIS_LOG_FILE
 if [ -z "$REDIS_LOG_FILE" ] ; then
-	REDIS_LOG_FILE=$_REDIS_LOG_FILE
-	echo "Selected default - $REDIS_LOG_FILE"
+	_MANUAL_EXECUTION=true
+	#read the redis log file path
+	_REDIS_LOG_FILE="/var/log/redis_$REDIS_PORT.log"
+	read -p "Please select the redis log file name [$_REDIS_LOG_FILE] " REDIS_LOG_FILE
+	if [ -z "$REDIS_LOG_FILE" ] ; then
+		REDIS_LOG_FILE=$_REDIS_LOG_FILE
+		echo "Selected default - $REDIS_LOG_FILE"
+	fi
 fi
 
-
-#get the redis data directory
-_REDIS_DATA_DIR="/var/lib/redis/$REDIS_PORT"
-read -p "Please select the data directory for this instance [$_REDIS_DATA_DIR] " REDIS_DATA_DIR
 if [ -z "$REDIS_DATA_DIR" ] ; then
-	REDIS_DATA_DIR=$_REDIS_DATA_DIR
-	echo "Selected default - $REDIS_DATA_DIR"
+	_MANUAL_EXECUTION=true
+	#get the redis data directory
+	_REDIS_DATA_DIR="/var/lib/redis/$REDIS_PORT"
+	read -p "Please select the data directory for this instance [$_REDIS_DATA_DIR] " REDIS_DATA_DIR
+	if [ -z "$REDIS_DATA_DIR" ] ; then
+		REDIS_DATA_DIR=$_REDIS_DATA_DIR
+		echo "Selected default - $REDIS_DATA_DIR"
+	fi
 fi
 
-#get the redis executable path
-_REDIS_EXECUTABLE=`command -v redis-server`
-read -p "Please select the redis executable path [$_REDIS_EXECUTABLE] " REDIS_EXECUTABLE
 if [ ! -x "$REDIS_EXECUTABLE" ] ; then
-	REDIS_EXECUTABLE=$_REDIS_EXECUTABLE
-
+	_MANUAL_EXECUTION=true
+	#get the redis executable path
+	_REDIS_EXECUTABLE=`command -v redis-server`
+	read -p "Please select the redis executable path [$_REDIS_EXECUTABLE] " REDIS_EXECUTABLE
 	if [ ! -x "$REDIS_EXECUTABLE" ] ; then
-		echo "Mmmmm...  it seems like you don't have a redis executable. Did you run make install yet?"
-		exit 1
+		REDIS_EXECUTABLE=$_REDIS_EXECUTABLE
+
+		if [ ! -x "$REDIS_EXECUTABLE" ] ; then
+			echo "Mmmmm...  it seems like you don't have a redis executable. Did you run make install yet?"
+			exit 1
+		fi
 	fi
 fi
 
@@ -112,7 +143,9 @@ echo "Data dir       : $REDIS_DATA_DIR"
 echo "Executable     : $REDIS_EXECUTABLE"
 echo "Cli Executable : $CLI_EXEC"
 
-read -p "Is this ok? Then press ENTER to go on or Ctrl-C to abort." _UNUSED_
+if $_MANUAL_EXECUTION == true ; then
+	read -p "Is this ok? Then press ENTER to go on or Ctrl-C to abort." _UNUSED_
+fi
 
 mkdir -p `dirname "$REDIS_CONFIG_FILE"` || die "Could not create redis config directory"
 mkdir -p `dirname "$REDIS_LOG_FILE"` || die "Could not create redis log dir"