diff --git a/install.sh b/install.sh
index 637a21da..ab305e9e 100755
--- a/install.sh
+++ b/install.sh
@@ -1,34 +1,49 @@
 #!/bin/sh
 set -e
-if [ "$1" != "" ]; then
-	if [ -d "$1" ]; then
-		mkdir -p $1/tools/agbcc
-		mkdir -p $1/tools/agbcc/bin
-		mkdir -p $1/tools/agbcc/include
-		mkdir -p $1/tools/agbcc/lib
-		cp agbcc $1/tools/agbcc/bin/
-		cp old_agbcc $1/tools/agbcc/bin/
-		cp agbcc_arm $1/tools/agbcc/bin/
-		cp -R libc/include $1/tools/agbcc/ #drop include, because we don't want include/include
-		cp ginclude/* $1/tools/agbcc/include/
-		cp libgcc.a $1/tools/agbcc/lib/
-		cp libc.a $1/tools/agbcc/lib/
-		echo "agbcc successfully installed!"
+
+if [ "$1" = "-h" ]; then
+	echo "Usage: install.sh PATH"
+	exit 0
+fi
+
+# If there's no installation directory specified, the install script will default to 
+# installing agbcc into /opt/pret/agbcc
+if [ "$1" = "" ]; then
+	BASE_INSTALL_DIRECTORY=/opt/pret
+	INSTALL_DIRECTORY=$BASE_INSTALL_DIRECTORY
+	mkdir -p $INSTALL_DIRECTORY
+else
+	BASE_INSTALL_DIRECTORY=$1
+	INSTALL_DIRECTORY=$BASE_INSTALL_DIRECTORY/tools
+fi
+
+# The BASE_INSTALL_DIRECTORY nomenclature is so that the check for the existence of the 
+# directory doesn't fail just because there's no tools directory yet.
+if [ -d "$BASE_INSTALL_DIRECTORY" ]; then
+	mkdir -p $INSTALL_DIRECTORY/agbcc
+	mkdir -p $INSTALL_DIRECTORY/agbcc/bin
+	mkdir -p $INSTALL_DIRECTORY/agbcc/include
+	mkdir -p $INSTALL_DIRECTORY/agbcc/lib
+	cp agbcc $INSTALL_DIRECTORY/agbcc/bin/
+	cp old_agbcc $INSTALL_DIRECTORY/agbcc/bin/
+	cp agbcc_arm $INSTALL_DIRECTORY/agbcc/bin/
+	cp -R libc/include $INSTALL_DIRECTORY/agbcc/ #drop include, because we don't want include/include
+	cp ginclude/* $INSTALL_DIRECTORY/agbcc/include/
+	cp libgcc.a $INSTALL_DIRECTORY/agbcc/lib/
+	cp libc.a $INSTALL_DIRECTORY/agbcc/lib/
+	echo "agbcc successfully installed!"
+else
+	if [ -d "../$BASE_INSTALL_DIRECTORY" ]; then
+		echo "Target directory does not exist. Did you mean to do \"./install.sh ../$1\"?"
 	else
-		if [ -d "../$1" ]; then
-			echo "Target directory does not exist. Did you mean to do \"./install.sh ../$1\"?"
+		if case $BASE_INSTALL_DIRECTORY in ".."*) true;; *) false;; esac; then
+			echo "Target directory does not exist. If you aren't familiar with relative paths, make sure that agbcc and the repository are in the same directory, and run \"./install.sh $1\" again."
 		else
-			if case $1 in ".."*) true;; *) false;; esac; then
-				echo "Target directory does not exist. If you aren't familiar with relative paths, make sure that agbcc and the repository are in the same directory, and run \"./install.sh $1\" again."
+			if echo "$BASE_INSTALL_DIRECTORY" | grep -qE '^[^/]*.$'; then
+				echo "Target directory does not exist. You probably meant to do \"./install.sh ../$1\", but agbcc and $1 do not exist in the same directory. Check your spelling, make sure that the repository has been cloned, ensure that agbcc and the repository are in the same directory, and run \"./install.sh ../$1\" again."
 			else
-				if echo "$1" | grep -qE '^[^/]*.$'; then
-					echo "Target directory does not exist. You probably meant to do \"./install.sh ../$1\", but agbcc and $1 do not exist in the same directory. Check your spelling, make sure that the repository has been cloned, ensure that agbcc and the repository are in the same directory, and run \"./install.sh ../$1\" again."
-				else
-					echo "Target directory does not exist. Check your spelling, re-read the instructions, and try again."
-				fi
+				echo "Target directory does not exist. Check your spelling, re-read the instructions, and try again."
 			fi
 		fi
 	fi
-else
-	echo "Usage: install.sh PATH"
 fi