find_file paths exts Find a file among all provided paths, trying
various extensiosn exts. Return the first combination of paths
find_file paths exts
Find real filename of an executable.
Copy a file.
Create a directory.
mkdir_parent f tgt Create a directory and its parent, call f with
directory name created, in order.
mkdir_parent f tgt
Remove a directory.
Expand a filename containing '*.ext' into corresponding
Test file existence, considering case even on case insensitive filesystem.