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Comment by Outpox | Hacker News Reader

For someone who hasn't done any Perl yet and only little Python could you explain why?

For the specific thing the OP mentioned, this:

    $ perl -pi -e 's/MY_NAME/Marco/g' ./*.txt

... would go through all "*.txt" files in the directory, and globally replace the token "MY_NAME" with "Marco".

Great for a {poor man's,simple and easy to understand} basic template system to be used inside a bash script ;)

Overkill. Just use:

    $ sed -i 's,MY_NAME,Marco,g' *.txt

nope. I've dealt recently with some big DB files (I think GB size) and regex doing the same. sed is a lot slower than perl for this kind of task.

I don't know how sed and perl compare, but I know these things:

Use a C local (e.g. LANG=C or LC_ALL=C) for dramatic speed up of tools like grep/sort and probably also sed. If you don't do that, usually the UTF-8 parser kicks in, which is a lot slower.

Perl is actually well known to have a non-optimal regex implementation: https://swtch.com/~rsc/regexp/regexp1.html That said, I don't know how fast it is (what optimizations it has) at simple string substitutions.

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