diff --git a/t/t-clean.sh b/t/t-clean.sh
index 806778e6..2e34f2bd 100755
--- a/t/t-clean.sh
+++ b/t/t-clean.sh
@@ -67,8 +67,8 @@ begin_test "clean stdin"
   git init "$reponame"
   cd "$reponame"
 
-  base64 /dev/urandom | head -c 1024 > small.dat
-  base64 /dev/urandom | head -c 2048 > large.dat
+  base64 < /dev/urandom | head -c 1024 > small.dat
+  base64 < /dev/urandom | head -c 2048 > large.dat
 
   expected_small="$(calc_oid_file "small.dat")"
   expected_large="$(calc_oid_file "large.dat")"
diff --git a/t/t-fsck.sh b/t/t-fsck.sh
index 24278da4..1e594d32 100755
--- a/t/t-fsck.sh
+++ b/t/t-fsck.sh
@@ -142,7 +142,7 @@ create_invalid_pointers() {
   ext="${2:-dat}"
 
   git cat-file blob ":$valid" | awk '{ sub(/$/, "\r"); print }' >"crlf.$ext"
-  base64 /dev/urandom | head -c 1025 >"large.$ext"
+  base64 < /dev/urandom | head -c 1025 >"large.$ext"
   git \
     -c "filter.lfs.process=" \
     -c "filter.lfs.clean=cat" \
diff --git a/t/t-malformed-pointers.sh b/t/t-malformed-pointers.sh
index fe80e25a..c40e3828 100755
--- a/t/t-malformed-pointers.sh
+++ b/t/t-malformed-pointers.sh
@@ -14,10 +14,10 @@ begin_test "malformed pointers"
   git add .gitattributes
   git commit -m "initial commit"
 
-  base64 /dev/urandom | head -c 1023 > malformed_small.dat
-  base64 /dev/urandom | head -c 1024 > malformed_exact.dat
-  base64 /dev/urandom | head -c 1025 > malformed_large.dat
-  base64 /dev/urandom | head -c 1048576 > malformed_xxl.dat
+  base64 < /dev/urandom | head -c 1023 > malformed_small.dat
+  base64 < /dev/urandom | head -c 1024 > malformed_exact.dat
+  base64 < /dev/urandom | head -c 1025 > malformed_large.dat
+  base64 < /dev/urandom | head -c 1048576 > malformed_xxl.dat
 
   git \
     -c "filter.lfs.process=" \