improve gz function

See mathiasbynens#1044

Author: Okeanos

stow/shell/dot-functions

@@ -85,7 +85,10 @@ function server() {
 # Compare original and gzipped file size
 function gz() {
 	local origsize gzipsize ratio
-	origsize=$(wc -c <"${1}")
+	origsize=$(
+ 		stat -Lf"%z" -- "$1" 2> /dev/null; # macOS `stat`
+ 		stat -Lc"%s" -- "$1" 2> /dev/null; # GNU `stat`
+ 	);
 	gzipsize=$(gzip -c "${1}" | wc -c)
 	ratio=$(echo "${gzipsize} * 100 / ${origsize}" | bc -l)
 	printf "orig: %d bytes\n" "${origsize}"