Each path may be a font file or a directory, either absolute or relative to the current directory. All subdirectories of a given directory are searched for font files. Don't specify directory names that are symbolic links, however, since (at least some versions of) find(1) won't dereference them.
A font's destination is determined by variables in the file texmf.cnf. By default, fontimport will issue a warning to stderr instead of overwriting an existing font file. The -f flag forces overwriting.
fontimport can cope with font names conforming the 8.3-namescheme, too, so you can import fonts from either a TDS-compliant or MSDOS installation. emTeX's font libraries are not supported. If you want to import fonts from a font library, you need to unpack it with emTeX's fontlib utility first.
The full pathname of each font successfully imported is echoed to stdout. When fontimport can not parse a font's name, it will import the font using a path element of "/unknown/" and issue a warning on stderr.
fontimport tries to guess the mode of PK files. With the -m flag you may specify a fallback mode to be used if the mode can't be guessed.