The original GDSII specification was very strict about characters that could be used in structure (cell) names. Characters were limited to:

Upper Case A-Z

Numerals 0-9

Special Characters: $ _ [ ] ( )

31 total characters

CAD implementations of GDSII writers soon began to violate these rules once the original Calma workstations were no longer dominant. For example, some systems began using lower case characters in the names. Some readers would treat the upper and lower case version of a character as the same and some differentiated between the two. Some would fail if structure names contained lower case characters.

The text "fixer" directives were implemented primarily as a service to users who were running into these naming problems. The available options are:

Command Line     Function
   Option
-------------    --------
   -lc           change all text strings and structure names to lower case. (implies -names)

   -uc           change all text strings and structure names  to upper case. (implies -names)

  -names        repair all dubious structure names. but does not touch text strings (exclusive)