A long time ago I wrote a reformatting utility for a client in sed, because my manager didn't want to have to support the utility and Anderson claimed it couldn't be done in any language. The Androids whined and then they rewrote it in C++, which they had to support.

> However sed is perfect if you have spare time and want to write basic programs in unnecessarily complex way for fun.

There are certain things that are difficult to do in sed, but are much easier to do in ed. Though ed doesn't have the branch command and labels, having essentially random access throughout the file makes up for it.

Sed does not have a debugger that is 50 years old. The author was not saying that sed is a bad tool; he's saying it doesn't have a debugger. If there is a desire to have a debugger for the tool, that has existed for 50 years without having one, perhaps the tool is not being used in the way it has been used for the last 50 years. This would seem to make the argument that the tool has been tried and tested less relevant.

COBOL was written in the 60s and has been in mission critical stuff for decades. Neither of those factors means it's the right tool for the job now.

The things I'm recommending that are more mature are Go, Python, D, Rust, or any other language that is more verbose and maintainable than regular expressions. Anything with a full debugger, IDE support, and useful error messages is a better choice.