for loop includes wild characters (*.c) if no files with extension .c. How do I get around? [duplicate]

you need to set nullglob before your loop

shopt -s nullglob

nullglob: If set, bash allows patterns which match no files (see Pathname Expansion above) to expand to a null string, rather than themselves.

When you're done and want to reset it to the original behavior, use:

shopt -u nullglob

As pointed out by Dennis Williamson in one of the comments.

CodeHunter