Fixed Issue #6596

Fixed the block comments at the top of the source file and the help message for the script (starting at line 279) so that an underscore ("_") character is correctly described as the separator for the first message field name rather than a period character "."

Tools/sdlog2/sdlog2_dump.py

@@ -4,7 +4,9 @@ from __future__ import print_function
 
 """Dump binary log generated by PX4's sdlog2 or APM as CSV
     
-Usage: python sdlog2_dump.py <log.bin> [-v] [-e] [-d delimiter] [-n null] [-m MSG[.field1,field2,...]]
+Usage: python sdlog2_dump.py <log.bin> [-v] [-e] [-d delimiter] [-n null] [-m MSG[_field1,field2,...]]
+
+Example Usage: python sdlog2_dump.py log.bin -m GPS_Lat,Lng -m AHR2_Roll,Pitch,Yaw
     
     -v  Use plain debug output instead of CSV.
     
@@ -14,9 +16,10 @@ Usage: python sdlog2_dump.py <log.bin> [-v] [-e] [-d delimiter] [-n null] [-m MS
     
     -n  Use "null" as placeholder for empty values in CSV. Default is empty.
     
-    -m MSG[.field1,field2,...]
+    -m MSG[_field1,field2,...]
         Dump only messages of specified type, and only specified fields.
-        Multiple -m options allowed."""
+        Multiple -m options allowed.
+	"""
 
 __author__  = "Anton Babushkin"
 __version__ = "1.2"
@@ -273,12 +276,12 @@ class SDLog2Parser:
 
 def _main():
     if len(sys.argv) < 2:
-        print("Usage: python sdlog2_dump.py <log.bin> [-v] [-e] [-d delimiter] [-n null] [-m MSG[.field1,field2,...]] [-t TIME_MSG_NAME]\n")
+        print("Usage: python sdlog2_dump.py <log.bin> [-v] [-e] [-d delimiter] [-n null] [-m MSG[_field1,field2,...]] [-t TIME_MSG_NAME]\n")
         print("\t-v\tUse plain debug output instead of CSV.\n")
         print("\t-e\tRecover from errors.\n")
         print("\t-d\tUse \"delimiter\" in CSV. Default is \",\".\n")
         print("\t-n\tUse \"null\" as placeholder for empty values in CSV. Default is empty.\n")
-        print("\t-m MSG[.field1,field2,...]\n\t\tDump only messages of specified type, and only specified fields.\n\t\tMultiple -m options allowed.")
+        print("\t-m MSG[_field1,field2,...]\n\t\tDump only messages of specified type, and only specified fields.\n\t\tMultiple -m options allowed.")
         print("\t-t\tSpecify TIME message name to group data messages by time and significantly reduce duplicate output.\n")
         print("\t-fPrint to file instead of stdout")
         return