Python vs Bash - In which kind of tasks each one outruns the other performance-wise? [closed]

Answer 1

Generally, bash works better than python only in those environments where python is not available. :)

Seriously, I have to deal with both languages daily, and will take python instantly over bash if given the choice. Alas, I am forced to use bash on certain "small" platforms because someone has (mistakenly, IMHO) decided that python is "too large" to fit.

While it is true that bash might be faster than python for some select tasks, it can never be as quick to develop with, or as easy to maintain (at least after you get past 10 lines of code or so). Bash's sole strong point wrt python or ruby or lua, etc., is its ubiquity.

Answer 2

When you writing scripts performance does not matter (in most cases).
If you care about performance 'Python vs Bash' is a false question.

Python:
+ easier to write
+ easier to maintain
+ easier code reuse (try to find universal error-proof way to include files with common code in sh, I dare you)
+ you can do OOP with it too!
+ easier arguments parsing. well, not easier, exactly. it still will be too wordy to my taste, but python have argparse facility built in.
- ugly ugly 'subprocess'. try to chain commands and not to cry a river how ugly your code will become. especially if you care about exit codes.

Bash:
+ ubiquity, as was said earlier, indeed.
+ simple commands chaining. that's how you glue together different commands in a simple way. Also Bash (not sh) have some improvements, like pipefail, so chaining is really short and expressive.
+ do not require 3rd-party programs to be installed. can be executed right away.
- god, it's full of gotchas. IFS, CDPATH.. thousands of them.

If one writing a script bigger than 100 LOC: choose Python
If one need path manipulation in script: choose Python(3)
If one need somewhat like alias but slightly complicated: choose Bash/sh

Anyway, one should try both sides to get the idea what are they capable of.

Maybe answer can be extended with packaging and IDE support points, but I'm not familiar with this sides.

As always you have to choose from turd sandwich and giant douche. And remember, just a few years ago Perl was new hope. Where it is now.

Answer 3

If you are looking to cobble together a quick utility with minimal effort, bash is good. For a wrapper round an application, bash is invaluable.

Anything that may have you coming back over and over to add improvements is probably (though not always) better suited to a language like Python as Bash code comprising over a 1000 lines gets very painful to maintain. Bash code is also irritating to debug when it gets long.......

Part of the problem with these kind of questions is, from my experience, that shell scripts are usually all custom tasks. There have been very few shell scripting tasks that I have come across where there is already a solution freely available.

Answer 4

Developer efficiency matters much more to me in scenarios where both bash and Python are sensible choices.

Some tasks lend themselves well to bash, and others to Python. It also isn't unusual for me to start something as a bash script and change it to Python as it evolves over several weeks.

A big advantage Python has is in corner cases around filename handling, while it has glob, shutil, subprocess, and others for common scripting needs.

Answer 5

Performance wise both can do equally the same, so the question becomes which saves more development time?

Bash relies on calling other commands, and piping them for creating new ones. This has the advantage that you can quickly create new programs just with the code borrowed from other people, no matter what programming language they used.

This also has the side effect of resisting change in sub-commands pretty well, as the interface between them is just plain text.

Additionally Bash is very permissive on how you can write on it. This means it will work well for a wider variety of context, but it also relies on the programmer having the intention of coding in a clean safe manner. Otherwise Bash won't stop you from building a mess.

Python is more structured on style, so a messy programmer won't be as messy. It will also work on operating systems outside Linux, making it instantly more appropriate if you need that kind of portability.

But it isn't as simple for calling other commands. So if your operating system is Unix most likely you will find that developing on Bash is the fastest way to develop.

When to use Bash:

• It's a non graphical program, or the engine of a graphical one.
• It's only for Unix.

When to use Python:

• It's a graphical program.
• It shall work on Windows.

Answer 6

There are 2 scenario's where Bash performance is at least equal I believe:

• Scripting of command line utilities
• Scripts which take only a short time to execute; where starting the Python interpreter takes more time than the operation itself

That said, I usually don't really concern myself with performance of the scripting language itself. If performance is a real issue you don't script but program (possibly in Python).