すみません、こんな感じです。

> ri StringIO#string
/cygdrive/c/Documents: No such file or directory
and: No such file or directory
Settings/my-name/ri_1608.0: No such file or directory
sh: /cygdrive/c/Documents: No such file or directory
-------------------------------------------------------- StringIO#string
strio.string -> string
------------------------------------------------------------------------
Returns underlying String object, the subject of IO.