Use interpreter from $PATH instead of absolute paths in various scripts using /usr/bin/env (#9689)

On NixOS, `bash` isn't under `/bin/bash` but rather in some directory in `$PATH`. Locally, I've been patching those scripts to make them work.

`/usr/bin/env` seems to be the only [portable way](https://unix.stackexchange.com/questions/29608/why-is-it-better-to-use-usr-bin-env-name-instead-of-path-to-name-as-my) to use binaries from the PATH as interpreters.

Signed-off-by: Quentin Gliech <quentingliech@gmail.com>

17 files changed, 18 insertions, 17 deletions

diff --git a/.buildkite/scripts/test_old_deps.sh b/.buildkite/scripts/test_old_deps.sh
index 28e6694b5d..9fe5b696b0 100755
--- a/.buildkite/scripts/test_old_deps.sh
+++ b/.buildkite/scripts/test_old_deps.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 # this script is run by buildkite in a plain `xenial` container; it installs the
 # minimal requirements for tox and hands over to the py35-old tox environment.
diff --git a/.buildkite/scripts/test_synapse_port_db.sh b/.buildkite/scripts/test_synapse_port_db.sh
index 9ed2177635..8914319e38 100755
--- a/.buildkite/scripts/test_synapse_port_db.sh
+++ b/.buildkite/scripts/test_synapse_port_db.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 #
 # Test script for 'synapse_port_db', which creates a virtualenv, installs Synapse along
 # with additional dependencies needed for the test (such as coverage or the PostgreSQL
diff --git a/changelog.d/9689.misc b/changelog.d/9689.misc
new file mode 100644
index 0000000000..a08d3482ad
--- /dev/null
+++ b/changelog.d/9689.misc
@@ -0,0 +1 @@
+Use interpreter from `$PATH` via `/usr/bin/env` instead of absolute paths in various scripts.
diff --git a/contrib/purge_api/purge_history.sh b/contrib/purge_api/purge_history.sh
index e7dd5d6468..c45136ff53 100644
--- a/contrib/purge_api/purge_history.sh
+++ b/contrib/purge_api/purge_history.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 # this script will use the api:
 #    https://github.com/matrix-org/synapse/blob/master/docs/admin_api/purge_history_api.rst
diff --git a/contrib/purge_api/purge_remote_media.sh b/contrib/purge_api/purge_remote_media.sh
index 77220d3bd5..4930d9529c 100644
--- a/contrib/purge_api/purge_remote_media.sh
+++ b/contrib/purge_api/purge_remote_media.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 DOMAIN=yourserver.tld
 # add this user as admin in your home server:
diff --git a/demo/clean.sh b/demo/clean.sh
index 418ca9457e..6b809f6e83 100755
--- a/demo/clean.sh
+++ b/demo/clean.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 set -e
 
diff --git a/demo/start.sh b/demo/start.sh
index f6b5ea137f..621a5698b8 100755
--- a/demo/start.sh
+++ b/demo/start.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 DIR="$( cd "$( dirname "$0" )" && pwd )"
 
diff --git a/demo/stop.sh b/demo/stop.sh
index 85a1d2c161..f9dddc5914 100755
--- a/demo/stop.sh
+++ b/demo/stop.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 DIR="$( cd "$( dirname "$0" )" && pwd )"
 
diff --git a/docker/build_debian.sh b/docker/build_debian.sh
index f312f0715f..f426d2b77b 100644
--- a/docker/build_debian.sh
+++ b/docker/build_debian.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 # The script to build the Debian package, as ran inside the Docker image.
 
diff --git a/docker/run_pg_tests.sh b/docker/run_pg_tests.sh
index d18d1e4c8e..1fd08cb62b 100755
--- a/docker/run_pg_tests.sh
+++ b/docker/run_pg_tests.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 # This script runs the PostgreSQL tests inside a Docker container. It expects
 # the relevant source files to be mounted into /src (done automatically by the
diff --git a/scripts-dev/check-newsfragment b/scripts-dev/check-newsfragment
index 448cadb829..af6d32e332 100755
--- a/scripts-dev/check-newsfragment
+++ b/scripts-dev/check-newsfragment
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 #
 # A script which checks that an appropriate news file has been added on this
 # branch.
diff --git a/scripts-dev/config-lint.sh b/scripts-dev/config-lint.sh
index 9132160463..8c6323e59a 100755
--- a/scripts-dev/config-lint.sh
+++ b/scripts-dev/config-lint.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 # Find linting errors in Synapse's default config file.
 # Exits with 0 if there are no problems, or another code otherwise.
 
diff --git a/scripts-dev/generate_sample_config b/scripts-dev/generate_sample_config
index 9cb4630a5c..02739894b5 100755
--- a/scripts-dev/generate_sample_config
+++ b/scripts-dev/generate_sample_config
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 #
 # Update/check the docs/sample_config.yaml
 
diff --git a/scripts-dev/lint.sh b/scripts-dev/lint.sh
index fe2965cd36..9761e97594 100755
--- a/scripts-dev/lint.sh
+++ b/scripts-dev/lint.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 #
 # Runs linting scripts over the local Synapse checkout
 # isort - sorts import statements
diff --git a/scripts-dev/make_full_schema.sh b/scripts-dev/make_full_schema.sh
index b8d1e636f1..bc8f978660 100755
--- a/scripts-dev/make_full_schema.sh
+++ b/scripts-dev/make_full_schema.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 #
 # This script generates SQL files for creating a brand new Synapse DB with the latest
 # schema, on both SQLite3 and Postgres.
diff --git a/scripts-dev/next_github_number.sh b/scripts-dev/next_github_number.sh
index 376280025a..00e9b14569 100755
--- a/scripts-dev/next_github_number.sh
+++ b/scripts-dev/next_github_number.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 set -e
 
@@ -6,4 +6,4 @@ set -e
 # next PR number.
 CURRENT_NUMBER=`curl -s "https://api.github.com/repos/matrix-org/synapse/issues?state=all&per_page=1" | jq -r ".[0].number"`
 CURRENT_NUMBER=$((CURRENT_NUMBER+1))
-echo $CURRENT_NUMBER
\ No newline at end of file
+echo $CURRENT_NUMBER
diff --git a/test_postgresql.sh b/test_postgresql.sh
index 1ffcaabd31..c10828fbbc 100755
--- a/test_postgresql.sh
+++ b/test_postgresql.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 # This script builds the Docker image to run the PostgreSQL tests, and then runs
 # the tests.