That's not as easy as cat something | grep "this" | cut -f 1 | sed -e 's/.../......

masklinn · on Sept 19, 2019

> That's not as easy as

> cat something | grep "this" | cut -f 1 | sed -e 's/.../.../'

Literally none of this is actually useful if you're already in Python:

    (
        line.split('\t')[0].replace(…, …)
        for line in open('something')
        if 'this' in line
    )

> You end up writing too much code

I can believe that if you're calling to external processes to perform operations which are pretty much trivial in the language.

kamaal · on Sept 19, 2019

Of course, if you plan to use one $language alone, you can do anything in that $language.

This question is specific to pipes.

masklinn · on Sept 19, 2019

> Of course, if you plan to use one $language alone, you can do anything in that $language.

That's missing what I'm noting though, which is that you don't need pipes anywhere near a shell script if you can simply do more of your work in-language. Case in point being that the entire pipeline you cited as an issue has no reason to exist outside of a shell or shell script.

kamaal · on Sept 20, 2019

That's because regexes are an another pain in Python, You have to write a lot of boiler plate exception handling code. Plus the same boiler plate code for file operations.

It doesn't feel like the language was designed for these tasks.

Too · on Sept 21, 2019

You forgot setting -e and -o pipefail. In case "something" is missing or can't be read for some other reason, your script will just continue happily without warning.

But oh, if you do set -o pipefail the grep will stop the whole pipeline when none of the lines matches "this". So you have to keep fiddling with ${PIPESTATUS[0]}. And none of pipefail or PIPESTATUS are really portable.

Not so simple after all.