feat: replace /bin/bash with /usr/bin/env bash (#3087)

This allows system which don't have this location (looking at you NixOS)
to run the scripts.

Author: fionera

CHANGELOG.md

@@ -70,6 +70,7 @@ END_UNRELEASED_TEMPLATE
 * (gazelle) Switched back to smacker/go-tree-sitter, fixing
   [#2630](https://github.com/bazel-contrib/rules_python/issues/2630)
 * (ci) We are now testing on Ubuntu 22.04 for RBE and non-RBE configurations.
+* (core) #!/usr/bin/env bash is now used as a shebang in the stage1 bootstrap template.
 
 {#v0-0-0-fixed}
 ### Fixed

addlicense.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 # Copyright 2023 The Bazel Authors. All rights reserved.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");

docs/readthedocs_build.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 set -eou pipefail
 

python/private/interpreter_tmpl.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 # --- begin runfiles.bash initialization v3 ---
 # Copy-pasted from the Bazel Bash runfiles library v3.

python/private/print_toolchain_checksums.bzl

@@ -27,7 +27,7 @@ def print_toolchains_checksums(name):
 
     template = """\
 cat > "$@" <<'EOF'
-#!/bin/bash
+#!/usr/bin/env bash
 set -euo pipefail
 
 set -o errexit -o nounset -o pipefail

python/private/stage1_bootstrap_template.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 set -e
 

python/uv/private/lock.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 set -euo pipefail
 
 if [[ -n "${BUILD_WORKSPACE_DIRECTORY:-}" ]]; then

sphinxdocs/private/sphinx_run_template.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 declare -a args
 %SETUP_ARGS%

tests/bootstrap_impls/external_binary_test.sh

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 set -euxo pipefail
 
 tmpdir="${TEST_TMPDIR}/external_binary"

tests/integration/bazel_from_env

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 #
 # A simple wrapper so rules_bazel_integration_test can use the
 # bazel version inherited from the environment.