command not found

I'm trying to use something like this: find . -type f -newermt 2007-06-07 ! -newermt 2007-06-08 -iname "*file*.txt" But get a "command not found" error - and it looks like it's because of -newermt I'm reasonaly sure I've used the above command in the past. Has something changed with macOS...

dear all, My mac mini late 2012 has been upgraded to Mac OS X El Capitan. Yet recently when I tried to configure the resolution via switchresx, the system said that the system integrity protection of El Capitan prevents such act. So I started up the mac mini pressing command r and enter the...