Bsd sed
From wikinotes
Sed allows you to search/replace within lines/files.
See also gnu sed.
Documentation
man sed
https://www.freebsd.org/cgi/man.cgi?query=sed&apropos=0&sektion=0&manpath=FreeBSD+13.0-RELEASE+and+Ports&arch=default&format=html
Overview
See gnu sed.
Differences from GNU
# BSD replace file contents sed -i ".bak" "s_aaa_bbb_g" /path/to/file