Index: Demo/comparisons/sortingtest.py
===================================================================
--- Demo/comparisons/sortingtest.py	(revisão 86657)
+++ Demo/comparisons/sortingtest.py	(cópia de trabalho)
@@ -23,6 +23,26 @@
 # - Outputs the sorted fields with exactly one space between them
 # - Handles blank input lines correctly
 
+USAGE = '''
+ Usage:
+
+ $ echo var1=23 other=14 ditto=23 fred=2 | python3 sortingtest.py
+ fred=2 other=14 ditto=23 var1=23
+
+ Or you can use a file with the same standard:
+
+ $ python3 sortingtest.py < names.txt
+ fred=2 other=14 ditto=23 var1=23
+
+ There is an alternative to enter the pattern in the command line:
+ Type <ENTER> in the end of the line.
+ To stop you can use the EOF, Ctrl+D on Linux.
+
+ $ python3 sortingtest.py
+ var1=23 other=14 ditto=23 fred=2
+ fred=2 other=14 ditto=23 var1=23
+'''
+
 import re
 import sys
 
@@ -42,4 +62,8 @@
             print("%s=%s" % (var, num), end=' ')
         print()
 
-main()
+def usage():
+    print(USAGE)
+
+if __name__ == '__main__':
+    main()