s a set of newline-separated strings
  -e, --regexp=PATTERN        use PATTERN as a regular expression
  -f, --file=FILE             obtain PATTERN from FILE
  -i, --ignore-case           ignore case distinctions
  -W, --workflow-flag=FLAG    select messages with FLAG
  -S, --sticky-flag=FLAG      select messages with FLAG
  -v, --invert-match          output only the messages that do not match any
                              selection criterion