Finding base words - problem

[epixoip]

brew install sed

Error: No available formula for sed
Searching formulae...
gnu-sed minised sedna ssed

Ok, so clearly you'd want gnu-sed there. Not too difficult.

I thought when u meant GNU sed you wanted me to try -i command, I have tryed original command, that is what it was giving me the original error:

No, I mean that your sed program comes from BSD, not GNU, and thus has several differences. In other words, not all sed implementations are the same, and this is true for most all userspace tools between BSD, GNU, and SVR4. Generally the GNU versions are much more feature-rich and typically result in non-portable commands.

That said, you can try adding the -E switch to that statement on BSD sed, that may enable the command to run (though it may not necessarily operate the same.) Or proceed with installing GNU sed per the above.