diff --git a/dotfiles/lib/functions/add_to_path b/dotfiles/lib/functions/add_to_path
new file mode 100755
index 00000000..7053bb82
--- /dev/null
+++ b/dotfiles/lib/functions/add_to_path
@@ -0,0 +1,7 @@
+#!/usr/bin/env sh
+
+function add_to_path {
+	path_lines "$2" | { cat -; echo "$1" } | path_from_lines
+}
+
+add_to_path "$@"
diff --git a/dotfiles/lib/functions/join_by_char b/dotfiles/lib/functions/join_by_char
new file mode 100755
index 00000000..5490f0d8
--- /dev/null
+++ b/dotfiles/lib/functions/join_by_char
@@ -0,0 +1,22 @@
+#!/usr/bin/env sh
+
+function join_by_char {
+    delimiter="$1"
+    if [ -z "$delimiter" ]; then
+        echo "Please specify a delimiter."
+        return 1
+    fi
+
+    while IFS= read -r line; do
+        # Append the line to the result with the delimiter, but not for the first line
+        if [ -z "$result" ]; then
+            result="$line"
+        else
+            result="$result$delimiter$line"
+        fi
+    done
+
+    echo "$result"
+}
+
+join_by_char "$@"
diff --git a/dotfiles/lib/functions/nixpkgs_source b/dotfiles/lib/functions/nixpkgs_source
new file mode 100755
index 00000000..02b5e4d0
--- /dev/null
+++ b/dotfiles/lib/functions/nixpkgs_source
@@ -0,0 +1,7 @@
+#!/usr/bin/env sh
+
+function nixpkgs_source {
+	nix eval  --expr '<nixpkgs>' --impure
+}
+
+nixpkgs_source
diff --git a/dotfiles/lib/functions/path_from_lines b/dotfiles/lib/functions/path_from_lines
new file mode 100755
index 00000000..776a055c
--- /dev/null
+++ b/dotfiles/lib/functions/path_from_lines
@@ -0,0 +1,7 @@
+#!/usr/bin/env sh
+
+function path_from_lines {
+	join_by_char ":"
+}
+
+path_from_lines "$@"
diff --git a/dotfiles/lib/functions/path_lines b/dotfiles/lib/functions/path_lines
index 03321e1f..bca39da6 100755
--- a/dotfiles/lib/functions/path_lines
+++ b/dotfiles/lib/functions/path_lines
@@ -1,7 +1,8 @@
 #!/usr/bin/env sh
 
 function path_lines {
-	split_by_char ":" "$PATH"
+	var="${1:-PATH}"
+	split_by_char ":" "${!var}"
 }
 
-path_lines
+path_lines "$@"