find . -name \*~ ! -newermt `date +%F -s yesterday`Find *~ files modified newer than yesterday:
find . -name \*~ -newermt `date +%F -s yesterday`Find *~ files between certain days:
find . -name \*~ -newermt `date +%F -s '14 days ago'` ! -newermt `date +%F -s '7 days ago'`