case sensitivity

text Whether a text matching operation distinguishes

upper-case (capital) letters from lower case (is "case

sensitive") or not ("case insensitive").

Case in file names should be preserved (for readability) but

ignored when matching (so the user doesn't have to get it

right). MS-DOS does not preserve case in file names, Unix

preserves case and matches are case sensitive.

Any decent text editor will allow the user to specify

whether or not text searches should be case sensitive.

Case sensitivity is also relevant in programming (most

programming languages distiguish between case in the names of

identifiers), and addressing (Internet domain names are

case insensitive but RFC 822 local mailbox names are case

sensitive).

Case insensitive operations are sometimes said to "fold case",

from the idea of folding the character code table so that

upper and lower case letters coincide. The alternative "smash

case" is more likely to be used by someone who considers this

behaviour a misfeature or in cases where one case is

actually permanently converted to the other.

"MS-DOS will automatically smash case in the names of all

the files you create".

(1997-07-09)