diff --git a/t/helper/test-path-utils.c b/t/helper/test-path-utils.c
index ae091d9b3e..30211d6d64 100644
--- a/t/helper/test-path-utils.c
+++ b/t/helper/test-path-utils.c
@@ -291,6 +291,18 @@ int cmd__path_utils(int argc, const char **argv)
 		return !!res;
 	}
 
+	if (argc > 2 && !strcmp(argv[1], "file-size")) {
+		int res = 0, i;
+		struct stat st;
+
+		for (i = 2; i < argc; i++)
+			if (stat(argv[i], &st))
+				res = error_errno("Cannot stat '%s'", argv[i]);
+			else
+				printf("%"PRIuMAX"\n", (uintmax_t)st.st_size);
+		return !!res;
+	}
+
 	fprintf(stderr, "%s: unknown function name: %s\n", argv[0],
 		argv[1] ? argv[1] : "(there was none)");
 	return 1;
diff --git a/t/t0021-conversion.sh b/t/t0021-conversion.sh
index fd5f1ac649..e10f5f787f 100755
--- a/t/t0021-conversion.sh
+++ b/t/t0021-conversion.sh
@@ -24,7 +24,7 @@ generate_random_characters () {
 }
 
 file_size () {
-	perl -e 'print -s $ARGV[0]' "$1"
+	test-tool path-utils file-size "$1"
 }
 
 filter_git () {
diff --git a/t/t1050-large.sh b/t/t1050-large.sh
index 1a9b21b293..dcb4dbba67 100755
--- a/t/t1050-large.sh
+++ b/t/t1050-large.sh
@@ -8,7 +8,7 @@ test_description='adding and checking out large blobs'
 # This should be moved to test-lib.sh together with the
 # copy in t0021 after both topics have graduated to 'master'.
 file_size () {
-	perl -e 'print -s $ARGV[0]' "$1"
+	test-tool path-utils file-size "$1"
 }
 
 test_expect_success setup '
diff --git a/t/t5315-pack-objects-compression.sh b/t/t5315-pack-objects-compression.sh
index 34c47dae09..df970d7584 100755
--- a/t/t5315-pack-objects-compression.sh
+++ b/t/t5315-pack-objects-compression.sh
@@ -7,7 +7,7 @@ test_description='pack-object compression configuration'
 # This should be moved to test-lib.sh together with the
 # copy in t0021 after both topics have graduated to 'master'.
 file_size () {
-	perl -e 'print -s $ARGV[0]' "$1"
+	test-tool path-utils file-size "$1"
 }
 
 test_expect_success setup '
diff --git a/t/t9303-fast-import-compression.sh b/t/t9303-fast-import-compression.sh
index 856219f46a..5045f02a53 100755
--- a/t/t9303-fast-import-compression.sh
+++ b/t/t9303-fast-import-compression.sh
@@ -6,7 +6,7 @@ test_description='compression setting of fast-import utility'
 # This should be moved to test-lib.sh together with the
 # copy in t0021 after both topics have graduated to 'master'.
 file_size () {
-	perl -e 'print -s $ARGV[0]' "$1"
+	test-tool path-utils file-size "$1"
 }
 
 import_large () {