diff --git a/t/t0021-conversion.sh b/t/t0021-conversion.sh
index a20b9f58e3..cb72fa49de 100755
--- a/t/t0021-conversion.sh
+++ b/t/t0021-conversion.sh
@@ -22,7 +22,7 @@ generate_random_characters () {
 }
 
 file_size () {
-	cat "$1" | wc -c | sed "s/^[ ]*//"
+	perl -e 'print -s $ARGV[0]' "$1"
 }
 
 filter_git () {
@@ -40,10 +40,9 @@ test_cmp_count () {
 	actual=$2
 	for FILE in "$expect" "$actual"
 	do
-		sort "$FILE" | uniq -c | sed "s/^[ ]*//" |
-			sed "s/^\([0-9]\) IN: clean/x IN: clean/" |
-			sed "s/^\([0-9]\) IN: smudge/x IN: smudge/" >"$FILE.tmp" &&
-		mv "$FILE.tmp" "$FILE"
+		sort "$FILE" | uniq -c |
+		sed -e "s/^ *[0-9][0-9]*[ 	]*IN: /x IN: /" >"$FILE.tmp" &&
+		mv "$FILE.tmp" "$FILE" || return
 	done &&
 	test_cmp "$expect" "$actual"
 }