diff --git a/files/fish/functions/posix-source.fish b/files/fish/functions/posix-source.fish
new file mode 100644
index 0000000..1830430
--- /dev/null
+++ b/files/fish/functions/posix-source.fish
@@ -0,0 +1,8 @@
+function posix-source
+	for i in (cat $argv)
+		if test (echo $i | sed -E 's/^[[:space:]]*(.).+$/\\1/g') != "#"
+			set arr (string split -m1 = $i)
+			set -gx $arr[1] $arr[2]
+		end
+	end
+end