[Solved] sed -i error: sed: -e expression #1, char 44: invalid reference \1 on `s’ command’s RHS

How to Solve sed -i error:

sed -i.bak '/.*CMDLINE_LINUX.*/s#(.*)"#\1 net.ifnames=0"#' /etc/default/grub

always report the error: sed: -e expression #1, char 44: invalid reference \1 on `s’ command’s RHS

sed -i -r '/.*CMDLINE_LINUX.*/s#(.*)"#\1 net.ifnames=0"#' /etc/default/grub

Later we know that you need to add -r, because there is a backward reference – \1, and -i and -r should be written separately

ProgrammerAH