Comment by hrktb | Hacker News Reader

Comment by hrktb | Hacker News Reader

Parent Full thread

Then a lot of people don’t understand the limits of what they’re doing.

For instance piping though commands works fine until one character sequence is interpreted as EOF. The fun part is it will work most of the time, and when it fails nobody will understand why (“we didn’t touch anything”), and rewriting the thing will be a political nightmare (“it was working before and was only 3 lines, why you need so much time to redo it ?”)

I think most people (me included) don’t do enough shell programming to really know the trade-off of the one-liner vs doing it in groovy, so the latter becomes the safer option (rightly so IMO)

one character sequence is interpreted as EOF

I know this is just an example, but how would that happen?

You can hit EOF or EOT in a stream of UTF-8 or other multi-byte encoding as part of a character. There must be ways to have it handled through something that understands character encodings and workaround the issue, but I know that dumb shell piping will fumble on those.

    % printf '\x04\necho EOT is not EOF in a pipe.\n' | bash
    bash: line 1: $'\004': command not found
    EOT is not EOF in a pipe.
    %

Pipes do not contain line disciplines and thus do not do special character processing.

If you can do it as a one-liner in Bash, then you're not using the JVM. The benefit of using Apache Groovy for scripting is access to the JVM (and of course defining Gradle builds). If you don't need the JVM, then do it in Python or Ruby.

Reply on news.ycombinator.com