When I try to save a file, if I use special characters in the name (such as a colon, question mark, or exclamation point) in Windows I get a message saying that the file name is invalid.
Why is that?
There are several characters that have special meaning to Windows (and to DOS, where most of the characters originally came from)
A filename cannot contain any of the following characters:
\ / : * ? " < > |
/ is a switch (and also a directory separator).
\ is a directory separator.
: is a drive designator.
? are wildcards used in searching.
" is a way to allow spaces in parameters.
> are redirection that allow input and output of a program to come from, and go to, something other than screen/keyboard.
| is a pipe that allows output from one program to be used as input to the next.