[PATCH RESEND v3 03/15] scripts/jobserver-exec: add a help message

[Mauro Carvalho Chehab <mchehab+huawei@kernel.org>]

Currently, calling it without an argument shows an ugly error
message. Instead, print a message using pythondoc as description.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
---
 scripts/jobserver-exec | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/scripts/jobserver-exec b/scripts/jobserver-exec
index 40a0f0058733..ae23afd344ec 100755
--- a/scripts/jobserver-exec
+++ b/scripts/jobserver-exec
@@ -1,6 +1,15 @@
 #!/usr/bin/env python3
 # SPDX-License-Identifier: GPL-2.0+
 
+"""
+Determines how many parallel tasks "make" is expecting, as it is
+not exposed via any special variables, reserves them all, runs a subprocess
+with PARALLELISM environment variable set, and releases the jobs back again.
+
+See:
+    https://www.gnu.org/software/make/manual/html_node/POSIX-Jobserver.html#POSIX-Jobserver
+"""
+
 import os
 import sys
 
@@ -12,17 +21,12 @@ sys.path.insert(0, os.path.join(SRC_DIR, LIB_DIR))
 from jobserver import JobserverExec                  # pylint: disable=C0415
 
 
-"""
-Determines how many parallel tasks "make" is expecting, as it is
-not exposed via an special variables, reserves them all, runs a subprocess
-with PARALLELISM environment variable set, and releases the jobs back again.
-
-See:
-    https://www.gnu.org/software/make/manual/html_node/POSIX-Jobserver.html#POSIX-Jobserver
-"""
-
 def main():
     """Main program"""
+    if len(sys.argv) < 2:
+        name = os.path.basename(__file__)
+        sys.exit("usage: " + name +" command [args ...]\n" + __doc__)
+
     with JobserverExec() as jobserver:
         jobserver.run(sys.argv[1:])
 
-- 
2.51.0