這幾天看到一個很小巧的 filewatch gem ，可以對 files 做偵測，有四種 event 可以被偵測到，分別是

#   :create_initial - initially present file (so start at end for tail)

#   :create - file is created (new file after initial globs, start at 0)

#   :modify - file is modified (size increases)

#   :delete - file is deleted

還有提供一個 command globtail 是可以對整個資料夾作類似 tail 的動作，一有 append 類型的修改就會 fire event 包含檔名跟新增的 line 。