Made more portable by using grep -E

README.md

@@ -4,8 +4,9 @@ ls zero bash polyfill
 allows you to simulate the --zero option of ls from
 gnu coreutils v9, in earlier versions
 
-relies on coreutils (ls and tr), and grep with
-the -P option
+also works with bsdgrep, for usage on bsd and mac
+
+relies on coreutils (ls and tr), and grep
 
 simply source ls_zero.bash in your .bashrc,
-place it in /etc/profile.d, or similar
+place it in /etc/profile.d, or similar