sort.py: print usage if there are no arguments

And return a specific exit code, as suggested by @rusty-snake[1].

Escape the first line in the docstring to avoid printing a blank line as
the first line of the output.

[1] https://github.com/netblue30/firejail/pull/5429#discussion_r999637842

1 files changed, 8 insertions, 2 deletions

diff --git a/contrib/sort.py b/contrib/sort.py
index 5cd4045f0..388a29710 100755
--- a/contrib/sort.py
+++ b/contrib/sort.py
@@ -2,7 +2,7 @@
 # This file is part of Firejail project
 # Copyright (C) 2014-2022 Firejail Authors
 # License GPL v2
-"""
+"""\
 Sort the arguments of commands in profiles.
 
 Usage: ./sort.py [/path/to/profile ...]
@@ -25,6 +25,7 @@ Examples:
 Exit Codes:
   0: Success: No profiles needed fixing.
   1: Error: One or more profiles could not be processed correctly.
+  2: Error: Missing arguments.
   101: Info: One or more profiles were fixed.
 """
 
@@ -94,8 +95,13 @@ def fix_profile(filename):
 
 
 def main(args):
-    exit_code = 0
+    if len(args) < 1:
+        print(__doc__, file=stderr)
+        return 2
+
     print(f"sort.py: checking {len(args)} profile(s)...")
+
+    exit_code = 0
     for filename in args:
         try:
             if exit_code not in (1, 101):