diff --git a/.phpstorm.meta.php/options.meta.php b/.phpstorm.meta.php/options.meta.php
index 845f5d60..9430456b 100644
--- a/.phpstorm.meta.php/options.meta.php
+++ b/.phpstorm.meta.php/options.meta.php
@@ -11,7 +11,8 @@
 
     registerArgumentsSet(
         'option_names',
-        'docker.client.path', 'docker.socket.path', 'script.exit-early', 'step.clone-path'
+        'docker.client.path', 'docker.socket.path', 'script.bash-runner', 'script.exit-early', 'script.runner',
+        'step.clone-path'
     );
 
     expectedArguments(
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 60e1e025..935faa27 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,9 +8,20 @@ The format is based on [Keep a Changelog] and Pipelines adheres to
 [Semantic Versioning]: https://semver.org/spec/v2.0.0.html
 
 ## [unreleased]
+### Add
+- Run step scripts with `/bin/bash` if it is available; disable with
+  `script.bash-runner=false` for previous behaviour (#17)  (thanks
+  [Tim Clephas])
+- `script.runner` configuration parameter to change `/bin/sh`, the
+  default script runner
+### Change
+- `-c <name>=true` and `false` are now supported for boolean configuration
+   parameter `<value>`
 ### Fix
 - Fix cache and data directory creation mode, limit to user access only
 
+[Tim Clephas]: https://github.com/Timple
+
 ## [0.0.65] - 2022-04-24
 ### Add
 - `--show` and `--show-pipelines`: Annotate steps' conditions with `*C`
diff --git a/README.md b/README.md
index 0731c5e2..8a98822f 100644
--- a/README.md
+++ b/README.md
@@ -817,6 +817,8 @@ to use the development version for `pipelines`.
 - [x] Copy local composer cache into container for better
       (offline) usage in PHP projects (see
       [Populate Caches](doc/PIPELINES-CACHES.md#populate-caches))
+- [x] Run scripts with `/bin/bash` if available ([#17]) (*bash-runner*
+      feature)
 - [ ] Support for `BITBUCKET_DOCKER_HOST_INTERNAL` environment variable
       / host.docker.internal hostname within pipelines
 - [ ] Count `BITBUCKET_BUILD_NUMBER` on a per project basis (*build-number*
@@ -857,6 +859,7 @@ to use the development version for `pipelines`.
 - [ ] Override the default image name (`--default-image <name>`; never
   needed this for local run)
 
+[#17]: https://github.com/ktomk/pipelines/issues/17
 [#13]: https://github.com/ktomk/pipelines/issues/13
 
 ## References
diff --git a/bitbucket-pipelines.yml b/bitbucket-pipelines.yml
index 43602c12..41168cb3 100644
--- a/bitbucket-pipelines.yml
+++ b/bitbucket-pipelines.yml
@@ -355,6 +355,14 @@ pipelines:
               mkdir -p /dev/null && test
               echo "despite mkdir non-zero exit status ($?), this script part will be fine"
             - echo "ok."
+    bash-runner:
+      - step:
+          name: "bash runner"
+          image: ktomk/pipelines:ubuntu-bash
+          script:
+            - echo "$HELLO"
+            - source /etc/os-release
+            - echo "$PRETTY_NAME"
 
 definitions:
   caches:
diff --git a/doc/CONFIGURATION-PARAMETERS.md b/doc/CONFIGURATION-PARAMETERS.md
index 9fb3c009..8ac46bf8 100644
--- a/doc/CONFIGURATION-PARAMETERS.md
+++ b/doc/CONFIGURATION-PARAMETERS.md
@@ -25,6 +25,16 @@ host and within mount binds.
 
 [DCK_HOST]: https://docs.docker.com/engine/reference/commandline/cli/#environment-variables
 
+## `script.bash-runner`
+
+Conditionally run scripts with `/bin/bash` instead of `script.runner` (`/bin/sh`
+by default) if `/bin/bash` is a standard file and executable in the container.
+
+Setting `script.bash-runner` to `false` prevents this check.
+
+* Default: `true` (bool)
+* Related configuration parameter: [`script.runner`](#scriptrunner)
+
 ## `script.exit-early`
 
 Executing the step and after scripts use `set -e` to exit
@@ -37,6 +47,21 @@ after *any* shell pipe with a non-zero exit status.
 
 * Default: `false` (bool).
 
+## `script.runner`
+
+The default script runner (`/bin/sh`), step scripts are run with this command.
+
+The step script is passed to the runner via standard input. The runner must be
+executable in the container.
+
+When `script.bash-runner` is `true` (default), the `script.runner` may be
+overridden by `/bin/bash` if found in the container. This behaviour can be
+disabled by setting `script.bash-runner` is `false`.
+
+* Default: `/bin/sh`
+* Related configuration parameter: [`script.bash-runner`](#scriptbash-runner)
+* Related option: `--step-script`
+
 ## `step.clone-path`
 
 Mount point / destination of the project files within a pipeline step
diff --git a/lib/container/ubuntu-bash.sh b/lib/container/ubuntu-bash.sh
new file mode 100755
index 00000000..a2bec59e
--- /dev/null
+++ b/lib/container/ubuntu-bash.sh
@@ -0,0 +1,55 @@
+#!/bin/bash
+# this file is part of pipelines
+#
+# pipelines:ubuntu-bash docker image
+#
+# usage: ./ubuntu-bash.sh [<docker-cmd>]
+#
+#   <docker-cmd>    "docker" by default
+#
+# requirements: docker (or equivalent)
+#
+# rationale:
+#
+#   bitbucket pipelines runs the scripts with /bin/bash if available, so
+# a user asked for it and we need it to integrate with bash.
+#
+# <https://github.com/ktomk/pipelines/issues/17#issuecomment-1161612881>
+#
+set -euo pipefail
+IFS=$' \n\t'
+
+docker_cmd="${1-docker}"
+from="docker.io/ubuntu"
+tag="docker.io/ktomk/pipelines:ubuntu-bash"
+
+echo "build '${tag}' from '${from}' with ${docker_cmd}..."
+
+<<'DOCKERFILE' "${docker_cmd}" build --build-arg FROM="${from}" -t "${tag}" - | sed -e 's/^/  build: /'
+ARG FROM
+FROM $FROM
+RUN echo "HELLO=YOU" > ~/.bashrc
+SHELL ["/bin/bash", "-c"]
+DOCKERFILE
+
+echo "test '${tag}' ..."
+
+# shellcheck disable=SC2016
+"${docker_cmd}" run --rm "${tag}" /bin/bash -c '
+set -x
+echo "\$HELLO.......: $HELLO"
+echo "\$SHELL.......: $SHELL"
+echo "\$BASH_VERSION: $BASH_VERSION"
+/bin/bash --version
+which bash
+ls -lhi "$(which bash)"
+ls -lhi /bin/bash
+source /etc/os-release
+echo "$PRETTY_NAME"
+' 2>&1 | sed -e 's/^/  test.: /'
+
+echo "push '${tag}' ..."
+
+"${docker_cmd}" push "${tag}" | sed -e 's/^/  push.: /'
+
+echo "done."
diff --git a/src/Runner/StepScriptRunner.php b/src/Runner/StepScriptRunner.php
index 53121ec5..8e519b52 100644
--- a/src/Runner/StepScriptRunner.php
+++ b/src/Runner/StepScriptRunner.php
@@ -73,7 +73,15 @@ public function runStepScript(Step $step)
             $this->runner->getRunOpts()->getBoolOption('script.exit-early')
         );
 
-        $status = $this->execScript($buffer, $exec, $name);
+        $scriptRunner = $this->runner->getRunOpts()->getOption('script.runner');
+        if ($this->runner->getRunOpts()->getBoolOption('script.bash-runner')) {
+            $bashRunner = '/bin/bash';
+            0 === $exec->capture('docker', array(
+                'exec', $name, '/bin/sh', '-c', "test -f ${bashRunner} && test -x ${bashRunner}",
+            )) && $scriptRunner = $bashRunner;
+        }
+
+        $status = $this->execScript($buffer, $exec, $name, $scriptRunner);
         if (0 !== $status) {
             $streams->err(sprintf("script non-zero exit status: %d\n", $status));
         }
@@ -86,7 +94,7 @@ public function runStepScript(Step $step)
 
         $buffer = StepScriptWriter::writeAfterScript($script, $status);
 
-        $afterStatus = $this->execScript($buffer, $exec, $name);
+        $afterStatus = $this->execScript($buffer, $exec, $name, $scriptRunner);
         if (0 !== $afterStatus) {
             $streams->err(sprintf("after-script non-zero exit status: %d\n", $afterStatus));
         }
@@ -99,13 +107,14 @@ public function runStepScript(Step $step)
      * @param string $script "\n" terminated script lines
      * @param Exec $exec
      * @param string $name
+     * @param string $runner executable (absolute path), defaults to "/bin/sh"
      *
      * @return int
      */
-    private function execScript($script, Exec $exec, $name)
+    private function execScript($script, Exec $exec, $name, $runner = '/bin/sh')
     {
         $buffer = Lib::cmd("<<'SCRIPT' docker", array(
-                'exec', '-i', $name, '/bin/sh',
+                'exec', '-i', $name, $runner,
             )) . "\n";
         $buffer .= $script;
         $buffer .= "SCRIPT\n";
diff --git a/src/Runner/StepScriptWriter.php b/src/Runner/StepScriptWriter.php
index 9b28de14..f4038031 100644
--- a/src/Runner/StepScriptWriter.php
+++ b/src/Runner/StepScriptWriter.php
@@ -43,6 +43,7 @@ public static function writeStepScript(array $script, $scriptExitEarly = false)
     {
         $buffer = "# this /bin/sh script is generated from a pipeline script\n";
         $buffer .= "set -e\n";
+        $buffer .= 'test "$0" = "/bin/bash" && if [ -f ~/.bashrc ]; then source ~/.bashrc; fi' . "\n";
         $buffer .= self::generateScriptBody(
             $script,
             self::getLinePostCommand($scriptExitEarly)
diff --git a/src/Utility/ConfigOptions.php b/src/Utility/ConfigOptions.php
index e92ba165..4fc6a7c8 100644
--- a/src/Utility/ConfigOptions.php
+++ b/src/Utility/ConfigOptions.php
@@ -75,6 +75,7 @@ public function run()
     public function parse(Args $args)
     {
         $options = $this->options;
+        $booleans = array('true' => true, 'false' => false);
 
         while (null !== $setting = $args->getOptionArgument('c')) {
             list($name, $value) = explode('=', $setting, 2) + array('undef', null);
@@ -85,6 +86,7 @@ public function parse(Args $args)
                 throw new \InvalidArgumentException(sprintf('not a %s: "%s"', $name, $value));
             }
             $type = null === $default ? 'string' : gettype($default);
+            'boolean' === $type && $value = isset($booleans[$value]) ? $booleans[$value] : $value;
             settype($value, $type) && $options->definition[$name] = array($value);
         }
     }
diff --git a/src/Utility/Options.php b/src/Utility/Options.php
index 31828fdc..5d8d74e6 100644
--- a/src/Utility/Options.php
+++ b/src/Utility/Options.php
@@ -29,6 +29,8 @@ public static function create()
         $definition = array(
             'docker.socket.path' => array('/var/run/docker.sock', null),
             'docker.client.path' => array('/usr/bin/docker', null),
+            'script.runner' => array('/bin/sh', null),
+            'script.bash-runner' => array(true, null),
             'script.exit-early' => array(false, null),
             'step.clone-path' => array('/app', Types::ABSPATH),
         );
diff --git a/test/integration/Runner/Docker/Binary/RepositoryTest.php b/test/integration/Runner/Docker/Binary/RepositoryTest.php
index 46a1b621..c13846a4 100644
--- a/test/integration/Runner/Docker/Binary/RepositoryTest.php
+++ b/test/integration/Runner/Docker/Binary/RepositoryTest.php
@@ -132,6 +132,7 @@ public function testRunnerWithDeploy()
 
         $exec->expect('capture', 'docker', 0, 'container id by name');
         $exec->expect('capture', 'docker', 0, 'run container');
+        $exec->expect('capture', 'docker', 1, 'test for /bin/bash');
         $exec->expect('pass', '~^<<\'SCRIPT\' docker exec ~', 0, 'run step script');
         $exec->expect('capture', 'docker', 'kill');
         $exec->expect('capture', 'docker', 'rm');
diff --git a/test/unit/Runner/StepRunnerTest.php b/test/unit/Runner/StepRunnerTest.php
index e5903634..405790e2 100644
--- a/test/unit/Runner/StepRunnerTest.php
+++ b/test/unit/Runner/StepRunnerTest.php
@@ -97,6 +97,7 @@ public function testCopy()
             ->expect('capture', 'docker', 0, 'run step container')
             ->expect('pass', $this->deploy_copy_cmd, 0, 'copy deployment /app create')
             ->expect('pass', $this->deploy_copy_cmd_2, 0, 'copy deployment /app copy')
+            ->expect('capture', 'docker', 1, 'test for /bin/bash')
             ->expect('pass', '~ docker exec ~', 0, 'run step script')
             ->expect('capture', 'docker', 0, 'docker kill')
             ->expect('capture', 'docker', 0, 'docker rm');
@@ -161,6 +162,7 @@ public function testKeepContainerOnErrorWithNonExistentContainer()
         $exec
             ->expect('capture', 'docker', 1, 'no id for name of potential re-use')
             ->expect('capture', 'docker', 0, 'run the container')
+            ->expect('capture', 'docker', 1, 'test for /bin/bash')
             ->expect('pass', '~ docker exec ~', 255);
 
         $this->keepContainerOnErrorExecTest($exec);
@@ -176,6 +178,7 @@ public function testKeepContainerOnErrorWithExistingContainer()
         $exec = new ExecTester($this);
         $exec
             ->expect('capture', 'docker', $containerId) # id for name of potential re-use
+            ->expect('capture', 'docker', 1, 'test for /bin/bash')
             ->expect('pass', '~ docker exec ~', 255);
 
         $this->keepContainerOnErrorExecTest($exec, $containerId);
@@ -191,6 +194,7 @@ public function testZapExistingContainer()
             ->expect('capture', 'docker', 0, 'docker run step container')
             ->expect('pass', $this->deploy_copy_cmd, 0, 'deploy copy stage 1')
             ->expect('pass', $this->deploy_copy_cmd_2, 0, 'deploy copy stage 1')
+            ->expect('capture', 'docker', 1, 'test for /bin/bash')
             ->expect('pass', '~ docker exec ~', 0)
             ->expect('capture', 'docker', 0, 'docker kill')
             ->expect('capture', 'docker', 0, 'docker rm');
@@ -210,6 +214,7 @@ public function testKeepExistingContainer()
         $exec = new ExecTester($this);
         $exec
             ->expect('capture', 'docker', "123456789\n", 'existing id')
+            ->expect('capture', 'docker', 1, 'test for /bin/bash')
             ->expect('pass', '~ docker exec ~', 0);
 
         $runner = $this->createTestStepRunner($exec, (Flags::FLAG_DOCKER_KILL | Flags::FLAG_DOCKER_REMOVE) ^ Flags::FLAGS);
@@ -342,6 +347,7 @@ public function testRunStepWithPipDockerSocket()
         $exec->expect('capture', 'docker', $buffer, 'obtain socket bind');
         $exec->expect('capture', 'docker', 0, 'obtain mount bind');
         $exec->expect('capture', 'docker', 0, 'run');
+        $exec->expect('capture', 'docker', 1, 'test for /bin/bash');
         $exec->expect('pass', '~ docker exec ~', 0, 'script');
         $exec->expect('capture', 'docker', 0, 'kill');
         $exec->expect('capture', 'docker', 0, 'rm');
@@ -364,6 +370,7 @@ public function testDockerClientInjection()
         $exec
             ->expect('capture', 'docker', 1, 'no id for name of potential re-use')
             ->expect('capture', 'docker', 0, 'run the container')
+            ->expect('capture', 'docker', 1, 'test for /bin/bash')
             ->expect('pass', '~ docker exec ~', 0, 'run step script')
             ->expect('capture', 'docker', 0, 'kill')
             ->expect('capture', 'docker', 0, 'rm');
@@ -431,6 +438,7 @@ public function testDockerClientMount()
         $exec->expect('capture', 'docker', $buffer, 'obtain client bind');
         $exec->expect('capture', 'docker', 0, 'obtain mount bind');
         $exec->expect('capture', 'docker', 0, 'run');
+        $exec->expect('capture', 'docker', 1, 'test for /bin/bash');
         $exec->expect('pass', '~ docker exec ~', 0, 'script');
         $exec->expect('capture', 'docker', 0, 'kill');
         $exec->expect('capture', 'docker', 0, 'rm');
@@ -483,6 +491,7 @@ public function testArtifacts()
             ->expect('capture', 'docker', 0, 'docker run step container')
             ->expect('pass', $this->deploy_copy_cmd, 0)
             ->expect('pass', $this->deploy_copy_cmd_2, 0)
+            ->expect('capture', 'docker', 1, 'test for /bin/bash')
             ->expect('pass', '~ docker exec ~', 0)
             ->expect('capture', 'docker', './build/foo-package.tgz')
             ->expect('pass', 'docker exec -w /app \'*dry-run*\' tar c -f - build/foo-package.tgz | tar x -f - -C ' . $tmpProjectDir, 0)
@@ -504,6 +513,7 @@ public function testArtifactsNoMatch()
             ->expect('capture', 'docker', 0, 'docker run step container')
             ->expect('pass', $this->deploy_copy_cmd, 0)
             ->expect('pass', $this->deploy_copy_cmd_2, 0)
+            ->expect('capture', 'docker', 1, 'test for /bin/bash')
             ->expect('pass', '~ docker exec ~', 0)
             ->expect('capture', 'docker', './build/foo-package.tgz')
             ->expect('capture', 'docker', 0) # docker kill
@@ -527,6 +537,7 @@ public function testArtifactsFailure()
             ->expect('capture', 'docker', 0, 'docker run step container')
             ->expect('pass', $this->deploy_copy_cmd, 0)
             ->expect('pass', $this->deploy_copy_cmd_2, 0)
+            ->expect('capture', 'docker', 1, 'test for /bin/bash')
             ->expect('pass', '~ docker exec ~', 0)
             ->expect('capture', 'docker', './build/foo-package.tgz')
             ->expect(
@@ -571,6 +582,7 @@ public function testAfterScript()
         $exec
             ->expect('capture', 'docker', 1, 'zap')
             ->expect('capture', 'docker', 0, 'docker run step container')
+            ->expect('capture', 'docker', 1, 'test for /bin/bash')
             ->expect('pass', '~<<\'SCRIPT\' docker exec ~', 0, 'script')
             ->expect('pass', '~<<\'SCRIPT\' docker exec ~', 0, 'after-script')
             ->expect('capture', 'docker', 0, 'docker kill')
@@ -591,6 +603,7 @@ public function testAfterScriptFailing()
         $exec
             ->expect('capture', 'docker', 1, 'zap')
             ->expect('capture', 'docker', 0, 'docker run step container')
+            ->expect('capture', 'docker', 1, 'test for /bin/bash')
             ->expect('pass', '~<<\'SCRIPT\' docker exec ~', 0, 'script')
             ->expect('pass', '~<<\'SCRIPT\' docker exec ~', 123, 'after-script')
             ->expect('capture', 'docker', 0, 'docker kill')
@@ -616,6 +629,7 @@ public function testServicesObtainNetworkAndShutdown()
             ->expect('capture', 'docker', 1, 'zap')
             ->expect('capture', 'docker', 0, 'docker run step container')
             ->expect('capture', 'docker', 0, 'run services')
+            ->expect('capture', 'docker', 1, 'test for /bin/bash')
             ->expect('pass', '~<<\'SCRIPT\' docker exec ~', 0, 'script')
             ->expect('capture', 'docker', 0, 'docker kill')
             ->expect('capture', 'docker', 0, 'docker rm')
@@ -641,6 +655,7 @@ public function testCaches()
         $exec
             ->expect('capture', 'docker', 1, 'zap')
             ->expect('capture', 'docker', 0, 'docker run step container')
+            ->expect('capture', 'docker', 1, 'test for /bin/bash')
             ->expect('pass', '~<<\'SCRIPT\' docker exec ~', 0, 'script')
             ->expect('capture', '~^docker exec ~', 0, 'caches: map path')
             ->expect('capture', '~>.*/composer\.tar docker cp~', 0, 'caches: copy out')
@@ -676,6 +691,7 @@ public function testCachesPrePopulated()
             ->expect('capture', '~^docker exec ~', 0, 'caches: map path')
             ->expect('capture', '~^docker exec .* mkdir -p ~', 0, 'caches: mkdir in container')
             ->expect('capture', '~<.*/composer\.tar docker cp ~', 0, 'caches: copy in')
+            ->expect('capture', 'docker', 1, 'test for /bin/bash')
             ->expect('pass', '~<<\'SCRIPT\' docker exec ~', 0, 'script')
             ->expect('capture', '~^docker exec ~', 0, 'caches: map path')
             ->expect('capture', '~>.*/composer\.tar docker cp~', 0, 'caches: copy out')
diff --git a/test/unit/Runner/StepScriptRunnerTest.php b/test/unit/Runner/StepScriptRunnerTest.php
index 3c8928aa..71bbbdcd 100644
--- a/test/unit/Runner/StepScriptRunnerTest.php
+++ b/test/unit/Runner/StepScriptRunnerTest.php
@@ -40,6 +40,20 @@ public function testRunStepScript()
         $scriptRunner = new StepScriptRunner($runner, '*test-run*');
 
         $step = $this->createTestStepFromFixture('steps.yml');
+        $exec->expect('capture', 'docker', 1, 'test for /bin/bash');
+        $exec->expect('pass', '~^<<\'SCRIPT\' ~');
+
+        $actual = $scriptRunner->runStepScript($step);
+        self::assertSame(0, $actual);
+    }
+
+    public function testRunStepScriptWithBinBash()
+    {
+        $runner = $this->mockRunner($exec);
+        $scriptRunner = new StepScriptRunner($runner, '*test-run*');
+
+        $step = $this->createTestStepFromFixture('steps.yml');
+        $exec->expect('capture', 'docker', 0, 'test for /bin/bash');
         $exec->expect('pass', '~^<<\'SCRIPT\' ~');
 
         $actual = $scriptRunner->runStepScript($step);
@@ -53,6 +67,7 @@ public function testRunStepScriptAndAfterScript()
 
         $step = $this->createTestStepFromFixture('after-script.yml');
 
+        $exec->expect('capture', 'docker', 1, 'test for /bin/bash');
         $exec->expect('pass', '~^<<\'SCRIPT\' ~', 3);
         $exec->expect('pass', '~^<<\'SCRIPT\' ~', 1);
 
@@ -72,6 +87,7 @@ public function testRunStepScriptWithPipe()
 
         $step = $this->createTestStepFromFixture('pipe.yml', 1, 'branches/develop');
 
+        $exec->expect('capture', 'docker', 1, 'test for /bin/bash');
         $exec->expect('pass', '~^<<\'SCRIPT\' ~');
 
         $actual = $scriptRunner->runStepScript($step);
@@ -88,6 +104,7 @@ public function testRunStepScriptWithAfterScriptPipe()
 
         $this->expectOutputString('After script:' . "\n");
 
+        $exec->expect('capture', 'docker', 1, 'test for /bin/bash');
         $exec->expect('pass', '~^<<\'SCRIPT\' ~', 0, 'script');
         $exec->expect('pass', '~^<<\'SCRIPT\' ~', 0, 'after-script');