mbox2maildir をダウンロードして、mbox の位置と maildir の位置を引数に指定して mbox2maildir を実行すれば変換される。
$ wget 'http://untroubled.org/mbox2maildir' --2013-03-26 14:57:05-- http://untroubled.org/mbox2maildir Resolving untroubled.org... 69.5.1.51 Connecting to untroubled.org|69.5.1.51|:80... connected. HTTP request sent, awaiting response... 200 OK Length: 2233 (2.2K) [text/plain] Saving to: “mbox2maildir” 100%[========================>] 2,233 --.-K/s in 0s 2013-03-26 14:57:06 (40.7 MB/s) - “mbox2maildir” saved [2233/2233] $ perl mbox2maildir ~/mbox ~/Maildir/