csplit(1) --quiet --elide-empty-files restore-mail-dump.txt %27%3CREGEX_PATTERN%3E%27 %27%7B*%7D%27
split a file into sections determined by context lines
-s, --quiet, --silent
       do not print counts of output file sizes
-z, --elide-empty-files
       remove empty output files
source manpages: csplit