diff --git a/git-p4.py b/git-p4.py
index c0ca7becaf4861..dd38dbca221580 100755
--- a/git-p4.py
+++ b/git-p4.py
@@ -4360,6 +4360,7 @@ def run(self, args):
         init_cmd = ["git", "init"]
         if self.cloneBare:
             init_cmd.append("--bare")
+            os.environ["GIT_DIR"] = os.getcwd()
         retcode = subprocess.call(init_cmd)
         if retcode:
             raise subprocess.CalledProcessError(retcode, init_cmd)
diff --git a/t/lib-httpd.sh b/t/lib-httpd.sh
index 4c76e813e396bf..f15158b2c579c7 100644
--- a/t/lib-httpd.sh
+++ b/t/lib-httpd.sh
@@ -259,7 +259,7 @@ test_http_push_nonff () {
 
 	test_expect_success 'non-fast-forward push fails' '
 		cd "$REMOTE_REPO" &&
-		HEAD=$(git rev-parse --verify HEAD) &&
+		HEAD=$(git --git-dir=. rev-parse --verify HEAD) &&
 
 		cd "$LOCAL_REPO" &&
 		git checkout $BRANCH &&
@@ -270,7 +270,7 @@ test_http_push_nonff () {
 		(
 			cd "$REMOTE_REPO" &&
 			echo "$HEAD" >expect &&
-			git rev-parse --verify HEAD >actual &&
+			git --git-dir=. rev-parse --verify HEAD >actual &&
 			test_cmp expect actual
 		)
 	'
@@ -284,18 +284,16 @@ test_http_push_nonff () {
 	'
 
 	test_expect_${EXPECT_CAS_RESULT} 'force with lease aka cas' '
-		HEAD=$(	cd "$REMOTE_REPO" && git rev-parse --verify HEAD ) &&
+		HEAD=$(git --git-dir="$REMOTE_REPO" rev-parse --verify HEAD) &&
 		test_when_finished '\''
-			(cd "$REMOTE_REPO" && git update-ref HEAD "$HEAD")
+			git --git-dir="$REMOTE_REPO" update-ref HEAD "$HEAD"
 		'\'' &&
 		(
 			cd "$LOCAL_REPO" &&
 			git push -v --force-with-lease=$BRANCH:$HEAD origin
 		) &&
 		git rev-parse --verify "$BRANCH" >expect &&
-		(
-			cd "$REMOTE_REPO" && git rev-parse --verify HEAD
-		) >actual &&
+		git --git-dir="$REMOTE_REPO" rev-parse --verify HEAD >actual &&
 		test_cmp expect actual
 	'
 }
diff --git a/t/t0001-init.sh b/t/t0001-init.sh
index e4d32bb4d259f6..db2bf1001f1bd3 100755
--- a/t/t0001-init.sh
+++ b/t/t0001-init.sh
@@ -20,8 +20,8 @@ check_config () {
 		return 1
 	fi
 
-	bare=$(cd "$1" && git config --bool core.bare)
-	worktree=$(cd "$1" && git config core.worktree) ||
+	bare=$(git --git-dir="$1" config --bool core.bare)
+	worktree=$(git --git-dir="$1" config core.worktree) ||
 	worktree=unset
 
 	test "$bare" = "$2" && test "$worktree" = "$3" || {
@@ -77,6 +77,7 @@ test_expect_success 'plain nested through aliased command' '
 '
 
 test_expect_success 'plain nested in bare through aliased command' '
+	test_config_global safe.bareRepository all &&
 	(
 		git init --bare bare-ancestor-aliased.git &&
 		cd bare-ancestor-aliased.git &&
diff --git a/t/t0003-attributes.sh b/t/t0003-attributes.sh
index 582e207aa12eb1..3a34f5dbc24eaa 100755
--- a/t/t0003-attributes.sh
+++ b/t/t0003-attributes.sh
@@ -346,17 +346,14 @@ test_expect_success 'setup bare' '
 
 test_expect_success 'bare repository: check that .gitattribute is ignored' '
 	(
-		cd bare.git &&
-		(
-			echo "f	test=f" &&
-			echo "a/i test=a/i"
-		) >.gitattributes &&
-		attr_check f unspecified &&
-		attr_check a/f unspecified &&
-		attr_check a/c/f unspecified &&
-		attr_check a/i unspecified &&
-		attr_check subdir/a/i unspecified
-	)
+		echo "f	test=f" &&
+		echo "a/i test=a/i"
+	) >bare.git/.gitattributes &&
+	attr_check f unspecified --git-dir=bare.git &&
+	attr_check a/f unspecified --git-dir=bare.git &&
+	attr_check a/c/f unspecified --git-dir=bare.git &&
+	attr_check a/i unspecified --git-dir=bare.git &&
+	attr_check subdir/a/i unspecified --git-dir=bare.git
 '
 
 bad_attr_source_err="fatal: bad --attr-source or GIT_ATTR_SOURCE"
@@ -449,41 +446,32 @@ test_expect_success 'diff without repository with attr source' '
 '
 
 test_expect_success 'bare repository: with --source' '
-	(
-		cd bare.git &&
-		attr_check_source foo/bar/f f tag-1 &&
-		attr_check_source foo/bar/a/i n tag-1 &&
-		attr_check_source foo/bar/f unspecified tag-2 &&
-		attr_check_source foo/bar/a/i m tag-2 &&
-		attr_check_source foo/bar/g g tag-2 &&
-		attr_check_source foo/bar/g unspecified tag-1
-	)
+	attr_check_source foo/bar/f f tag-1 --git-dir=bare.git &&
+	attr_check_source foo/bar/a/i n tag-1 --git-dir=bare.git &&
+	attr_check_source foo/bar/f unspecified tag-2 --git-dir=bare.git &&
+	attr_check_source foo/bar/a/i m tag-2 --git-dir=bare.git &&
+	attr_check_source foo/bar/g g tag-2 --git-dir=bare.git &&
+	attr_check_source foo/bar/g unspecified tag-1 --git-dir=bare.git
 '
 
 test_expect_success 'bare repository: check that --cached honors index' '
-	(
-		cd bare.git &&
-		GIT_INDEX_FILE=../.git/index \
-		git check-attr --cached --stdin --all <../stdin-all |
-		sort >actual &&
-		test_cmp ../specified-all actual
-	)
+	GIT_INDEX_FILE=.git/index \
+	git --git-dir=bare.git check-attr --cached --stdin --all <stdin-all |
+	sort >actual &&
+	test_cmp specified-all actual
 '
 
 test_expect_success 'bare repository: test info/attributes' '
+	mkdir -p bare.git/info &&
 	(
-		cd bare.git &&
-		mkdir info &&
-		(
-			echo "f	test=f" &&
-			echo "a/i test=a/i"
-		) >info/attributes &&
-		attr_check f f &&
-		attr_check a/f f &&
-		attr_check a/c/f f &&
-		attr_check a/i a/i &&
-		attr_check subdir/a/i unspecified
-	)
+		echo "f	test=f" &&
+		echo "a/i test=a/i"
+	) >bare.git/info/attributes &&
+	attr_check f f --git-dir=bare.git &&
+	attr_check a/f f --git-dir=bare.git &&
+	attr_check a/c/f f --git-dir=bare.git &&
+	attr_check a/i a/i --git-dir=bare.git &&
+	attr_check subdir/a/i unspecified --git-dir=bare.git
 '
 
 test_expect_success 'binary macro expanded by -a' '
diff --git a/t/t0056-git-C.sh b/t/t0056-git-C.sh
index 2630e756dab732..6b7122add56b2b 100755
--- a/t/t0056-git-C.sh
+++ b/t/t0056-git-C.sh
@@ -57,11 +57,13 @@ test_expect_success 'Order should not matter: "--git-dir=a.git -C c" is equivale
 test_expect_success 'Effect on --work-tree option: "-C c/a.git --work-tree=../a"  is equivalent to "--work-tree=c/a --git-dir=c/a.git"' '
 	rm c/a/a.txt &&
 	git --git-dir=c/a.git --work-tree=c/a status >expected &&
+	test_config_global safe.bareRepository all &&
 	git -C c/a.git --work-tree=../a status >actual &&
 	test_cmp expected actual
 '
 
 test_expect_success 'Order should not matter: "--work-tree=../a -C c/a.git" is equivalent to "-C c/a.git --work-tree=../a"' '
+	test_config_global safe.bareRepository all &&
 	git -C c/a.git --work-tree=../a status >expected &&
 	git --work-tree=../a -C c/a.git status >actual &&
 	test_cmp expected actual
diff --git a/t/t1020-subdirectory.sh b/t/t1020-subdirectory.sh
index 9fdbb2af80e0a8..20d2d306fecdce 100755
--- a/t/t1020-subdirectory.sh
+++ b/t/t1020-subdirectory.sh
@@ -177,10 +177,7 @@ test_expect_success 'no file/rev ambiguity check inside a bare repo (explicit GI
 test_expect_success 'no file/rev ambiguity check inside a bare repo' '
 	test_when_finished "rm -fr foo.git" &&
 	git clone -s --bare .git foo.git &&
-	(
-		cd foo.git &&
-		git show -s HEAD
-	)
+	git --git-dir=foo.git show -s HEAD
 '
 
 test_expect_success SYMLINKS 'detection should not be fooled by a symlink' '
diff --git a/t/t1900-repo-info.sh b/t/t1900-repo-info.sh
index 39bb77dda0c327..6280da1efb426a 100755
--- a/t/t1900-repo-info.sh
+++ b/t/t1900-repo-info.sh
@@ -20,6 +20,7 @@ test_repo_info () {
 	repo_name=$3
 	key=$4
 	expected_value=$5
+	repo_flag=${6:--C}
 
 	test_expect_success "setup: $label" '
 		eval "$init_command $repo_name"
@@ -27,13 +28,13 @@ test_repo_info () {
 
 	test_expect_success "lines: $label" '
 		echo "$key=$expected_value" > expect &&
-		git -C "$repo_name" repo info "$key" >actual &&
+		git $repo_flag "$repo_name" repo info "$key" >actual &&
 		test_cmp expect actual
 	'
 
 	test_expect_success "nul: $label" '
 		printf "%s\n%s\0" "$key" "$expected_value" >expect &&
-		git -C "$repo_name" repo info --format=nul "$key" >actual &&
+		git $repo_flag "$repo_name" repo info --format=nul "$key" >actual &&
 		test_cmp_bin expect actual
 	'
 }
@@ -48,7 +49,7 @@ test_repo_info 'bare repository = false is retrieved correctly' \
 	'git init' 'nonbare' 'layout.bare' 'false'
 
 test_repo_info 'bare repository = true is retrieved correctly' \
-	'git init --bare' 'bare' 'layout.bare' 'true'
+	'git init --bare' 'bare' 'layout.bare' 'true' '--git-dir'
 
 test_repo_info 'shallow repository = false is retrieved correctly' \
 	'git init' 'nonshallow' 'layout.shallow' 'false'
diff --git a/t/t2400-worktree-add.sh b/t/t2400-worktree-add.sh
index 023e1301c8e68e..0f8c83764705e7 100755
--- a/t/t2400-worktree-add.sh
+++ b/t/t2400-worktree-add.sh
@@ -171,11 +171,8 @@ test_expect_success 'not die on re-checking out current branch' '
 '
 
 test_expect_success '"add" from a bare repo' '
-	(
-		git clone --bare . bare &&
-		cd bare &&
-		git worktree add -b bare-main ../there2 main
-	)
+	git clone --bare . bare &&
+	git -C bare --git-dir=. worktree add -b bare-main ../there2 main
 '
 
 test_expect_success 'checkout from a bare repo without "add"' '
@@ -186,15 +183,11 @@ test_expect_success 'checkout from a bare repo without "add"' '
 '
 
 test_expect_success '"add" default branch of a bare repo' '
-	(
-		git clone --bare . bare2 &&
-		cd bare2 &&
-		git worktree add ../there3 main &&
-		cd ../there3 &&
-		# Simple check that a Git command does not
-		# immediately fail with the current setup
-		git status
-	) &&
+	git clone --bare . bare2 &&
+	git -C bare2 --git-dir=. worktree add ../there3 main &&
+	# Simple check that a Git command does not
+	# immediately fail with the current setup
+	git status &&
 	cat >expect <<-EOF &&
 	init.t
 	EOF
diff --git a/t/t2406-worktree-repair.sh b/t/t2406-worktree-repair.sh
index f5f19b3169384f..cac448b57559c9 100755
--- a/t/t2406-worktree-repair.sh
+++ b/t/t2406-worktree-repair.sh
@@ -84,7 +84,7 @@ test_expect_success 'repair .git file from bare.git' '
 	git -C bare.git worktree add --detach ../corrupt &&
 	git -C corrupt rev-parse --absolute-git-dir >expect &&
 	rm -f corrupt/.git &&
-	git -C bare.git worktree repair &&
+	git -C bare.git --git-dir=. worktree repair &&
 	git -C corrupt rev-parse --absolute-git-dir >actual &&
 	test_cmp expect actual
 '
diff --git a/t/t5503-tagfollow.sh b/t/t5503-tagfollow.sh
index febe44104177e1..6d178d84dde811 100755
--- a/t/t5503-tagfollow.sh
+++ b/t/t5503-tagfollow.sh
@@ -168,16 +168,13 @@ test_expect_success 'new clone fetch main and tags' '
 
 test_expect_success 'fetch specific OID with tag following' '
 	git init --bare clone3.git &&
-	(
-		cd clone3.git &&
-		git remote add origin .. &&
-		git fetch origin $B:refs/heads/main &&
+	git --git-dir=clone3.git remote add origin "$PWD" &&
+	git --git-dir=clone3.git fetch origin $B:refs/heads/main &&
 
-		git -C .. for-each-ref >expect &&
-		git for-each-ref >actual &&
+	git for-each-ref >expect &&
+	git --git-dir=clone3.git for-each-ref >actual &&
 
-		test_cmp expect actual
-	)
+	test_cmp expect actual
 '
 
 test_done
diff --git a/t/t5505-remote.sh b/t/t5505-remote.sh
index e592c0bcde91e9..6d3d8510cae191 100755
--- a/t/t5505-remote.sh
+++ b/t/t5505-remote.sh
@@ -561,7 +561,7 @@ test_expect_success 'add --mirror && prune' '
 	mkdir mirror &&
 	(
 		cd mirror &&
-		git init --bare &&
+		git init --bare && GIT_DIR=. && export GIT_DIR &&
 		git remote add --mirror -f origin ../one
 	) &&
 	(
@@ -583,7 +583,7 @@ test_expect_success 'add --mirror setting HEAD' '
 	mkdir headmirror &&
 	(
 		cd headmirror &&
-		git init --bare -b notmain &&
+		git init --bare -b notmain && GIT_DIR=. && export GIT_DIR &&
 		git remote add --mirror -f origin ../one &&
 		test "$(git symbolic-ref HEAD)" = "refs/heads/main"
 	)
diff --git a/t/t5509-fetch-push-namespaces.sh b/t/t5509-fetch-push-namespaces.sh
index 095df1a7535d57..5167c16c1f05e1 100755
--- a/t/t5509-fetch-push-namespaces.sh
+++ b/t/t5509-fetch-push-namespaces.sh
@@ -88,7 +88,7 @@ test_expect_success 'mirroring a repository using a ref namespace' '
 
 test_expect_success 'hide namespaced refs with transfer.hideRefs' '
 	GIT_NAMESPACE=namespace \
-		git -C pushee -c transfer.hideRefs=refs/tags \
+		git -C pushee --git-dir=. -c transfer.hideRefs=refs/tags \
 		ls-remote "ext::git %s ." >actual &&
 	printf "$commit1\trefs/heads/main\n" >expected &&
 	test_cmp expected actual
@@ -97,7 +97,7 @@ test_expect_success 'hide namespaced refs with transfer.hideRefs' '
 test_expect_success 'check that transfer.hideRefs does not match unstripped refs' '
 	git -C pushee pack-refs --all &&
 	GIT_NAMESPACE=namespace \
-		git -C pushee -c transfer.hideRefs=refs/namespaces/namespace/refs/tags \
+		git -C pushee --git-dir=. -c transfer.hideRefs=refs/namespaces/namespace/refs/tags \
 		ls-remote "ext::git %s ." >actual &&
 	printf "$commit1\trefs/heads/main\n" >expected &&
 	printf "$commit0\trefs/tags/0\n" >>expected &&
@@ -107,7 +107,7 @@ test_expect_success 'check that transfer.hideRefs does not match unstripped refs
 
 test_expect_success 'hide full refs with transfer.hideRefs' '
 	GIT_NAMESPACE=namespace \
-		git -C pushee -c transfer.hideRefs="^refs/namespaces/namespace/refs/tags" \
+		git -C pushee --git-dir=. -c transfer.hideRefs="^refs/namespaces/namespace/refs/tags" \
 		ls-remote "ext::git %s ." >actual &&
 	printf "$commit1\trefs/heads/main\n" >expected &&
 	test_cmp expected actual
diff --git a/t/t5619-clone-local-ambiguous-transport.sh b/t/t5619-clone-local-ambiguous-transport.sh
index cce62bf78d3351..3e9aac9015a01d 100755
--- a/t/t5619-clone-local-ambiguous-transport.sh
+++ b/t/t5619-clone-local-ambiguous-transport.sh
@@ -21,7 +21,7 @@ test_expect_success 'setup' '
 	echo "secret" >sensitive/secret &&
 
 	git init --bare "$REPO" &&
-	test_commit_bulk -C "$REPO" --ref=main 1 &&
+	(GIT_DIR="$REPO" && export GIT_DIR && test_commit_bulk --ref=main 1) &&
 
 	git -C "$REPO" update-ref HEAD main &&
 	git -C "$REPO" update-server-info &&
diff --git a/t/t6020-bundle-misc.sh b/t/t6020-bundle-misc.sh
index 500c81b8a14237..82df105b47f0bd 100755
--- a/t/t6020-bundle-misc.sh
+++ b/t/t6020-bundle-misc.sh
@@ -594,9 +594,9 @@ do
 		reflist=$(git for-each-ref --format="%(objectname)") &&
 		git rev-list --objects --filter=$filter --missing=allow-any \
 			$reflist >expect &&
-		for repo in cloned unbundled
+		for opt in "--git-dir cloned" "-C unbundled"
 		do
-			git -C $repo rev-list --objects --missing=allow-any \
+			git $opt rev-list --objects --missing=allow-any \
 				$reflist >actual &&
 			test_cmp expect actual || return 1
 		done
diff --git a/t/t9210-scalar.sh b/t/t9210-scalar.sh
index 009437a5f3168f..54513c220b679a 100755
--- a/t/t9210-scalar.sh
+++ b/t/t9210-scalar.sh
@@ -88,7 +88,7 @@ test_expect_success 'scalar enlistments need a worktree' '
 	test_when_finished rm -rf bare test &&
 
 	git init --bare bare/src &&
-	! scalar register bare/src 2>err &&
+	! scalar -c safe.bareRepository=all register bare/src 2>err &&
 	grep "Scalar enlistments require a worktree" err &&
 
 	git init test/src &&
diff --git a/t/t9700/test.pl b/t/t9700/test.pl
index f83e6169e2c100..99b712b626cfd8 100755
--- a/t/t9700/test.pl
+++ b/t/t9700/test.pl
@@ -153,9 +153,12 @@ sub adjust_dirsep {
 chdir($abs_repo_dir);
 
 # open alternate bare repo
-my $r4 = Git->repository(Directory => "$abs_repo_dir/bare.git");
-is($r4->command_oneline(qw(log --format=%s)), "bare commit",
-	"log of bare repo works");
+{
+	local $ENV{GIT_DIR} = "$abs_repo_dir/bare.git";
+	my $r4 = Git->repository(Directory => "$abs_repo_dir/bare.git");
+	is($r4->command_oneline(qw(log --format=%s)), "bare commit",
+		"log of bare repo works");
+}
 
 # unquoting paths
 is(Git::unquote_path('abc'), 'abc', 'unquote unquoted path');