smew man page
smew — search related messages from Mew's database file
smew myid [mydb [mydir]]
The smew utility searches related messages from a Message-ID database file with SQLite 3 for Mew.
myid is a Message-ID of the message to search.
mydb is a database file name. (default: "~/Mail/id.db")
mydir is a directory part of the message in the database. Note that messages are contained as a relative path from "~/Mail". If multiple messages are found by myid , the first found one is preferred. However, the message whose directory is mydir is preferred to the first one.
The options are as follows:
Search a parent message only.
Search a child message only.