2 optimize read_file for smaller scalar slurps with no options
16 add options to read_dir
18 grep filter qr or code ref
23 restart sysread/write after a signal (or check i/o count)
29 check for objects/refs to filenames
31 add chmod mode to write_file
33 add perms (same as chmod?) to syswrite
35 check result of rename in atomic mode