CentOS 7's sed doesn't support -E, but CentOS 8 does. That might cause some confusion. Also, FYI, this is the link for the POSIX specification for sed: https:

CentOS 7's sed doesn't support -E, but CentOS 8 does. That might cause some confusion. Also, FYI, this is the link for the POSIX specification for sed: https://pubs.opengroup.org/onlinepubs/9699919799/utilities/sed.html https://pubs.opengroup.org/onlinepubs/9699919799/utilities/s... Notice that -i is not POSIX.