After installing Trader's Little Helper, you can use commands like the following to convert, create ffp etc.

rem : create and save original shn file's st5

"C:\Program Files (x86)\Trader's Little Helper\CmdlineApps\shntool" hash "E:\Pink Floyd\PF_1970-10-23 Santa Monica (master)\*.shn" >"E:\Pink Floyd\PF_1970-10-23 Santa Monica (master)\info.st5"

rem : convert shn to flac

"C:\Program Files (x86)\Trader's Little Helper\CmdlineApps\shntool" conv -o flac "E:\Pink Floyd\PF_1970-10-23 Santa Monica (master)\*.shn"

rem : create and save flac ffp

"C:\Program Files (x86)\Trader's Little Helper\CmdlineApps\metaflac" --show-md5sum "E:\Pink Floyd\PF_1970-10-23 Santa Monica (master)\*.flac" >"E:\Pink Floyd\PF_1970-10-23 Santa Monica (master)\info.ffp"

rem : delete shn file

del /F/Q "E:\Pink Floyd\PF_1970-10-23 Santa Monica (master)\*.shn"


I created some .bat files and mass converted all my shn to flac several years back