diff --git a/t/pack-refs-tests.sh b/t/pack-refs-tests.sh
index 81086c3690..2fdaccb6c7 100644
--- a/t/pack-refs-tests.sh
+++ b/t/pack-refs-tests.sh
@@ -354,8 +354,8 @@ do
 
 			# Create 14 additional references, which brings us to
 			# 15 together with the default branch.
-			printf "create refs/heads/loose-%d HEAD\n" $(test_seq 14) >stdin &&
-			git update-ref --stdin <stdin &&
+			test_seq -f "create refs/heads/loose-%d HEAD" 14 |
+			git update-ref --stdin &&
 			test_path_is_missing .git/packed-refs &&
 			git ${pack_refs} --auto --all &&
 			test_path_is_missing .git/packed-refs &&
@@ -379,8 +379,8 @@ do
 			test_line_count = 2 .git/packed-refs &&
 
 			# Create 15 loose references.
-			printf "create refs/heads/loose-%d HEAD\n" $(test_seq 15) >stdin &&
-			git update-ref --stdin <stdin &&
+			test_seq -f "create refs/heads/loose-%d HEAD" 15 |
+			git update-ref --stdin &&
 			git ${pack_refs} --auto --all &&
 			test_line_count = 2 .git/packed-refs &&
 
@@ -401,18 +401,14 @@ do
 
 			# Create 99 packed refs. This should cause the heuristic
 			# to require more than the minimum amount of loose refs.
-			test_seq 99 |
-			while read i
-			do
-				printf "create refs/heads/packed-%d HEAD\n" $i || return 1
-			done >stdin &&
-			git update-ref --stdin <stdin &&
+			test_seq -f "create refs/heads/packed-%d HEAD" 99 |
+			git update-ref --stdin &&
 			git ${pack_refs} --all &&
 			test_line_count = 101 .git/packed-refs &&
 
 			# Create 24 loose refs, which should not yet cause us to repack.
-			printf "create refs/heads/loose-%d HEAD\n" $(test_seq 24) >stdin &&
-			git update-ref --stdin <stdin &&
+			test_seq -f "create refs/heads/loose-%d HEAD" 24 |
+			git update-ref --stdin &&
 			git ${pack_refs} --auto --all &&
 			test_line_count = 101 .git/packed-refs &&
 
@@ -420,8 +416,8 @@ do
 			# Note that we explicitly do not check for strict
 			# boundaries here, as this also depends on the size of
 			# the object hash.
-			printf "create refs/heads/addn-%d HEAD\n" $(test_seq 10) >stdin &&
-			git update-ref --stdin <stdin &&
+			test_seq -f "create refs/heads/addn-%d HEAD" 10 |
+			git update-ref --stdin &&
 			git ${pack_refs} --auto --all &&
 			test_line_count = 135 .git/packed-refs
 		)
diff --git a/t/t0613-reftable-write-options.sh b/t/t0613-reftable-write-options.sh
index e334751759..26b716c75f 100755
--- a/t/t0613-reftable-write-options.sh
+++ b/t/t0613-reftable-write-options.sh
@@ -68,8 +68,8 @@ test_expect_success 'many refs results in multiple blocks' '
 	(
 		cd repo &&
 		test_commit initial &&
-		test_seq -f "update refs/heads/branch-%d HEAD" 200 >input &&
-		git update-ref --stdin <input &&
+		test_seq -f "update refs/heads/branch-%d HEAD" 200 |
+		git update-ref --stdin &&
 		git pack-refs &&
 
 		cat >expect <<-EOF &&
@@ -178,8 +178,8 @@ test_expect_success 'restart interval at every single record' '
 	(
 		cd repo &&
 		test_commit initial &&
-		test_seq -f "update refs/heads/branch-%d HEAD" 10 >input &&
-		git update-ref --stdin <input &&
+		test_seq -f "update refs/heads/branch-%d HEAD" 10 |
+		git update-ref --stdin &&
 		git -c reftable.restartInterval=1 pack-refs &&
 
 		cat >expect <<-EOF &&
@@ -218,8 +218,8 @@ test_expect_success 'object index gets written by default with ref index' '
 	(
 		cd repo &&
 		test_commit initial &&
-		test_seq -f "update refs/heads/branch-%d HEAD" 5 >input &&
-		git update-ref --stdin <input &&
+		test_seq -f "update refs/heads/branch-%d HEAD" 5 |
+		git update-ref --stdin &&
 		git -c reftable.blockSize=100 pack-refs &&
 
 		cat >expect <<-EOF &&
@@ -253,8 +253,8 @@ test_expect_success 'object index can be disabled' '
 	(
 		cd repo &&
 		test_commit initial &&
-		test_seq -f "update refs/heads/branch-%d HEAD" 5 >input &&
-		git update-ref --stdin <input &&
+		test_seq -f "update refs/heads/branch-%d HEAD" 5 |
+		git update-ref --stdin &&
 		git -c reftable.blockSize=100 -c reftable.indexObjects=false pack-refs &&
 
 		cat >expect <<-EOF &&
diff --git a/t/t1400-update-ref.sh b/t/t1400-update-ref.sh
index db7f5444da..0f68a7dd42 100755
--- a/t/t1400-update-ref.sh
+++ b/t/t1400-update-ref.sh
@@ -1380,16 +1380,16 @@ test_expect_success 'fails with duplicate ref update via symref' '
 
 test_expect_success ULIMIT_FILE_DESCRIPTORS 'large transaction creating branches does not burst open file limit' '
 (
-	test_seq -f "create refs/heads/%d HEAD" 33 >large_input &&
-	run_with_limited_open_files git update-ref --stdin <large_input &&
+	test_seq -f "create refs/heads/%d HEAD" 33 |
+	run_with_limited_open_files git update-ref --stdin &&
 	git rev-parse --verify -q refs/heads/33
 )
 '
 
 test_expect_success ULIMIT_FILE_DESCRIPTORS 'large transaction deleting branches does not burst open file limit' '
 (
-	test_seq -f "delete refs/heads/%d HEAD" 33 >large_input &&
-	run_with_limited_open_files git update-ref --stdin <large_input &&
+	test_seq -f "delete refs/heads/%d HEAD" 33 |
+	run_with_limited_open_files git update-ref --stdin &&
 	test_must_fail git rev-parse --verify -q refs/heads/33
 )
 '
diff --git a/t/t1460-refs-migrate.sh b/t/t1460-refs-migrate.sh
index 0e1116a319..5246468024 100755
--- a/t/t1460-refs-migrate.sh
+++ b/t/t1460-refs-migrate.sh
@@ -276,11 +276,11 @@ test_expect_success 'multiple reftable blocks with multiple entries' '
 	test_when_finished "rm -rf repo" &&
 	git init --ref-format=files repo &&
 	test_commit -C repo first &&
-	printf "create refs/heads/ref-%d HEAD\n" $(test_seq 5000) >stdin &&
-	git -C repo update-ref --stdin <stdin &&
+	test_seq -f "create refs/heads/ref-%d HEAD" 5000 |
+	git -C repo update-ref --stdin &&
 	test_commit -C repo second &&
-	printf "update refs/heads/ref-%d HEAD\n" $(test_seq 3000) >stdin &&
-	git -C repo update-ref --stdin <stdin &&
+	test_seq -f "update refs/heads/ref-%d HEAD" 3000 |
+	git -C repo update-ref --stdin &&
 	test_migration repo reftable true
 '
 
diff --git a/t/t5004-archive-corner-cases.sh b/t/t5004-archive-corner-cases.sh
index 027dedd976..df513a4269 100755
--- a/t/t5004-archive-corner-cases.sh
+++ b/t/t5004-archive-corner-cases.sh
@@ -176,8 +176,7 @@ test_expect_success EXPENSIVE,UNZIP,UNZIP_ZIP64_SUPPORT \
 	blob=$(echo $s | git hash-object -w --stdin) &&
 
 	# create tree containing 65500 entries of that blob
-	test_seq -f "100644 blob $blob\t%d" 1 65500 >tree &&
-	tree=$(git mktree <tree) &&
+	tree=$(test_seq -f "100644 blob $blob\t%d" 1 65500 | git mktree) &&
 
 	# zip it, creating an archive a bit bigger than 4GB
 	git archive -0 -o many-big.zip $tree &&
diff --git a/t/t5401-update-hooks.sh b/t/t5401-update-hooks.sh
index 17a46fd3ba..44ec875aef 100755
--- a/t/t5401-update-hooks.sh
+++ b/t/t5401-update-hooks.sh
@@ -134,8 +134,8 @@ test_expect_success 'pre-receive hook that forgets to read its input' '
 	EOF
 	rm -f victim.git/hooks/update victim.git/hooks/post-update &&
 
-	printf "create refs/heads/branch_%d main\n" $(test_seq 100 999) >input &&
-	git update-ref --stdin <input &&
+	test_seq -f "create refs/heads/branch_%d main" 100 999 |
+	git update-ref --stdin &&
 	git push ./victim.git "+refs/heads/*:refs/heads/*"
 '