CopyDir recursively copies a directory tree, attempting to preserve permissions.

CopyFile copies the contents of the file named src to the file named by dst.

FgrepStringInFile is a small hammer for looking for a literal string in a file.

FileExists checks a file's existence.

ListFilesInDir returns an array of files found in a directory.

PurgeDirectory removes all of the contents of a given directory, leaving the directory itself intact.

RandomFilenameBase generates a temporary filename for use in testing or whatever.