diff --git a/CHANGELOG b/CHANGELOG
index 90e94b4..a7e016f 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,5 +1,10 @@
 # Changelog
 
+## 2024-12-16
+- Rewrote build-index.sh to be POSIX-compliant
+- build-index.sh now takes two arguments. The first is the root directory of the
+JD system, and the second is the output directory.
+
 ## 2023-12-17
 
 Repository created
diff --git a/build-index.sh b/build-index.sh
index c23e96e..b2378f4 100755
--- a/build-index.sh
+++ b/build-index.sh
@@ -1,35 +1,83 @@
-#!/bin/bash
+#!/bin/sh
 
-# defin the target dir
-parent=$(dirname "${BASH_SOURCE[0]}")
-cd $parent; cd ../../../
-directory=$(pwd -P)
+# MIT License
+# 
+# Copyright (c) 2023 Cordelya Sharpe
+# Copyright (c) 2024 Emma Tebibyte <emma@tebibyte.media>
+# 
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+# 
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+# 
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
 
-today=`date "+%Y-%m-%d"`
+set -e
 
-echo -e "Date: $today\n"
+test -n "$DEBUG" && set -x
 
-for dirs in "$directory"/*; do
-	string="---\n"
-	area=$(basename "${dirs}")
-	if [ "$area" != "System Volume Information" ]; then
+if test -z "$2"; then
+	if test -z "$1"; then
+		# output to and read system from current dir if $1 and $2 are not set
+		out="$(pwd -P)"
+		root="$out"
+	else
+		# if $1 is set, that is the system root
+		root="$1"
+	fi
+else
+	# if both $1 and $2 are set, they are the root and output dir
+	root="$1"
+	out="$2"
+fi
 
-		string+="title: $area\n"
-		string+="date: $today\n"
-		string+="---\n\n"
-		for cats in "$dirs"/*; do
-			category=$(basename "${cats}")
-			string+="# $category\n\n"
-			for ids in "$cats"/*; do
-				ident=$(basename "${ids}")
-				string+="* $ident\n"
+date="$(date "+%Y-%m-%d")"
+
+# for every area dir in the root, get the basename of the area
+for dir in "$root"/*; do
+	area="$(basename "$dir")"
+
+	# only include jd files
+	if test -n "$(printf '%s\n' "$area" | sed -n '/^[0-9][0-9]-.*/p')"
+	then
+		# set the filename to the area number for the filename of the index
+		fullpath="$out/$(printf '%s\n' "$area" | dd bs=5 count=1 2>/dev/null).md"
+
+		# if the file already exists, back it up
+		if test -f "$fullpath"; then
+			mv "$fullpath" "$fullpath.old"
+		fi
+
+		printf '%s: %s: Saving index as %s.\n' "$0" "$area" "$fullpath" 1>&2
+
+		# add front matter to markdown file
+		printf -- "---\ntitle: %s\ndate: %s\n---\n" "$area" "$date" >>"$fullpath"
+
+		# iterate through catergories
+		for c in "$dir"/*; do
+			category="$(basename "$c")"
+			# add category as a header to the output file
+			printf "# %s\n\n" "$category" >>"$fullpath"
+
+			# iterate through contents of categories
+			for i in "$c"/*; do
+				id="$(basename "$i")"
+				# add each content item to the output file
+				printf "* %s\n" "$id" >>"$fullpath"
 			done
-		string+="\n"
+
+			printf '\n' >>"$fullpath"
 		done
-	savedir="$directory/00-09 Index/00 Index/00.01 Index/"
-	fname="${area:0:5}.md"
-	fullpath="$savedir$fname"
-	echo $fullpath
-	echo -e $string > "$fullpath"
 	fi
 done