find . -type f -exec grep -Li "maintenance" {} \+

Hierbei ist -L fuer alle Dateien die den Text nicht enthalten

L, --files-without-match
              Suppress normal output; instead print the name of each input file from which no  output  would  normally  have  been  printed.   The
              scanning will stop on the first match.

und kleines -l fuer Dateien die den Text enthalten.

-l, --files-with-matches
              Suppress  normal output; instead print the name of each input file from which output would normally have been printed.  The scanning
              will stop on the first match.