4 ms·

System level stuff sucks in Python. Dealing with files, I/O, permissions, etc is a real pain. It easily takes 5x as long and as many loc to do the same thing as

System level stuff sucks in Python. Dealing with files, I/O, permissions, etc is a real pain. It easily takes 5x as long and as many loc to do the same thing as in bash. I can see the benefit of dropping to a command block to, say, run a command and filter the output with some | grep | awk | sort of whatever, and then seamlessly come back up to a more fully featured language to deal with that data.

gorgoiler 5y ago
This is very true, particularly if your script is just an imperative list of commands to run. Python scripts win when you actually need to handle errors, or non trivial output parsing, or when the concept of “list of things” doesn’t fit neatly into the “lines of text / pipe symbol” paradigm. I try to think of it like Donkey Kong. Every time you do something like this: var=$(command | awk -vID=$ID ‘$6 ~ /foo/ and $7 == ID {print $1 “ “ $2} | head -3) …you get hit by a barrel. Three hits and you turn it into a Python module with a __main__.py or an if __name__ == “__main__” at the bottom. If it’s a truism that most shell scripts are better off written in Python, it’s just as true that all Python scripts are better off as reusable modules (that may also be standalone scripts.)
spsesk117 5y ago
I feel like you just described Perl, and I use Perl almost every day for this kind of thing, but people seem to hate it these days. The syntax can be weird, but I still think it really shines in cases like these.
sverhagen 5y ago
My experience is different. For me, Python has a good balance of readability, access to system functions and consistent, predictable interfaces. I'm not saying you're wrong, just that "it depends". I'm pretty adequate at writing BASH, but it's not my "daily driver" programming language, so I have to still try things out, google a lot of things that aren't easily obvious, and excessive trial and error. But as a Java programmer I also know that Java, with all of its abstractions and verbosity, is a complete non-starter for shell scripting. For me, Python has often been a helpful compromise. Part of this may also be that I've never learned to do a great job at organizing a BASH shell "project". So, those often get unwieldy maintenance nightmares. At plenty of time me and my peers have agreed: when your BASH script exceeds [some low number of] lines, find another language. Again, it matters a lot what your team's culture and comforts are. If that's BASH for you, then r.e.s.p.e.c.t.
- dahart 5y ago
  You’re comparing Python and Bash as programming languages, not as shells. Python’s great as a programming language, but it’s a terrible shell. Likewise, Bash is a terrible programming language, but as a shell is pretty good and is probably the most used shell. The point parent was making is that it’s far more difficult in Python to run a process, capture the output, and grep something from it, than it is in Bash. In Bash this is a one liner with extremely minimal syntax. In Python, this is a big multi-line affair invoking several modules and multiple functions. Python isn’t a shell purely because you can’t execute an executable file by typing the bare name of the file. Python also doesn’t pass the cut & paste test - you normally can’t paste snippets from somewhere into a Python repl due to indentation issues, this alone makes it very difficult to use as an interactive shell. And Python is not meant to be an interactive shell, so there isn’t much of a problem.
  - sverhagen 5y ago
    Sure, but the conversation had already evolved to "scripting languages" as opposed to command lines.
    - dahart 5y ago
      Where did that happen? The comment you replied to emphasized “system level stuff”. The comment before that emphasized “shells”.
IshKebab 5y ago
It might take a few more lines of code to do stuff in a real programming language like Python (I would recommend Deno actually) but at least there's a decent chance it will actually work reliably.
kerblang 5y ago
> then seamlessly come back up to a more fully featured language to deal with that data That's the thing - I don't see how you can do that. The command blocks return nil or error, but not the output, so that you'd have to dump that to a temporary file, scrape the file separately, remember to delete it, and so on. I can make it work, but it doesn't live up to the idea of seamlessness.

gorgoiler 5y ago

This is very true, particularly if your script is just an imperative list of commands to run. Python scripts win when you actually need to handle errors, or non trivial output parsing, or when the concept of “list of things” doesn’t fit neatly into the “lines of text / pipe symbol” paradigm. I try to think of it like Donkey Kong. Every time you do something like this: var=$(command | awk -vID=$ID ‘$6 ~ /foo/ and $7 == ID {print $1 “ “ $2} | head -3) …you get hit by a barrel. Three hits and you turn it into a Python module with a __main__.py or an if __name__ == “__main__” at the bottom. If it’s a truism that most shell scripts are better off written in Python, it’s just as true that all Python scripts are better off as reusable modules (that may also be standalone scripts.)

spsesk117 5y ago

I feel like you just described Perl, and I use Perl almost every day for this kind of thing, but people seem to hate it these days. The syntax can be weird, but I still think it really shines in cases like these.

sverhagen 5y ago

My experience is different. For me, Python has a good balance of readability, access to system functions and consistent, predictable interfaces. I'm not saying you're wrong, just that "it depends". I'm pretty adequate at writing BASH, but it's not my "daily driver" programming language, so I have to still try things out, google a lot of things that aren't easily obvious, and excessive trial and error. But as a Java programmer I also know that Java, with all of its abstractions and verbosity, is a complete non-starter for shell scripting. For me, Python has often been a helpful compromise. Part of this may also be that I've never learned to do a great job at organizing a BASH shell "project". So, those often get unwieldy maintenance nightmares. At plenty of time me and my peers have agreed: when your BASH script exceeds [some low number of] lines, find another language. Again, it matters a lot what your team's culture and comforts are. If that's BASH for you, then r.e.s.p.e.c.t.

dahart 5y ago
You’re comparing Python and Bash as programming languages, not as shells. Python’s great as a programming language, but it’s a terrible shell. Likewise, Bash is a terrible programming language, but as a shell is pretty good and is probably the most used shell. The point parent was making is that it’s far more difficult in Python to run a process, capture the output, and grep something from it, than it is in Bash. In Bash this is a one liner with extremely minimal syntax. In Python, this is a big multi-line affair invoking several modules and multiple functions. Python isn’t a shell purely because you can’t execute an executable file by typing the bare name of the file. Python also doesn’t pass the cut & paste test - you normally can’t paste snippets from somewhere into a Python repl due to indentation issues, this alone makes it very difficult to use as an interactive shell. And Python is not meant to be an interactive shell, so there isn’t much of a problem.
- sverhagen 5y ago
  Sure, but the conversation had already evolved to "scripting languages" as opposed to command lines.
  - dahart 5y ago
    Where did that happen? The comment you replied to emphasized “system level stuff”. The comment before that emphasized “shells”.

IshKebab 5y ago

It might take a few more lines of code to do stuff in a real programming language like Python (I would recommend Deno actually) but at least there's a decent chance it will actually work reliably.

kerblang 5y ago

> then seamlessly come back up to a more fully featured language to deal with that data That's the thing - I don't see how you can do that. The command blocks return nil or error, but not the output, so that you'd have to dump that to a temporary file, scrape the file separately, remember to delete it, and so on. I can make it work, but it doesn't live up to the idea of seamlessness.