tools/ci.sh: Add --bash-completion option.

Signed-off-by: Jeff Epler <jepler@unpythonic.net>

docs/develop/gettingstarted.rst

@@ -306,6 +306,22 @@ As an example, you can build and test the unix minimal port with:
 
    $ tools/ci.sh unix_minimal_build unix_minimal_run_tests
 
+If you use the bash shell, you can add a ``ci`` command with tab completion:
+
+.. code-block:: bash
+
+   $ eval `tools/ci.sh --bash-completion`
+   $ ci unix_cov<tab>
+
+This will complete the ci step name to ``unix_coverage_``.
+Pressing tab a second time will show the list of matching steps:
+
+.. code-block:: bash
+
+   $ ci unix_coverage_<tab>
+   unix_coverage_32bit_build
+   unix_coverage_32bit_run_native_mpy_tests…
+
 Folder structure
 ----------------
 

tools/ci.sh

@@ -1005,11 +1005,22 @@ function _ci_help {
     exit
 }
 
+function _ci_bash_completion {
+    echo "alias ci=\"$(readlink -f "$0")\"; complete -W '$(grep '^function ci_' $0 | awk '{print $2}' | sed 's/^ci_//')' ci"
+}
+
 function _ci_main {
     case "$1" in
         (-h|-?|--help)
             _ci_help
         ;;
+        (--bash-completion)
+            _ci_bash_completion
+        ;;
+        (-*)
+            echo "Unknown option: $1" 1>&2
+            exit 1
+        ;;
         (*)
             set -e
             cd $(dirname "$0")/..