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The suite of tools you're typically working with in bash (i.e. bash built-ins and basic stuff that comes on most linux systems) doesn't like arrays very much.

The suite of tools you're typically working with in bash (i.e. bash built-ins and basic stuff that comes on most linux systems) doesn't like arrays very much. It's generally more productive to split things into multiple lines and/or insert delimiters so that you can play to the strengths of the tools you have at your disposal. Everything is basically either a formatted input or a formatted output at the end of the day. Trying to shoehorn things into data "structures" that enable efficient access in certain cases rarely makes sense because of all the processing you need to do to get it there in the first place and it winds up being more efficient just deal in formatted streams of data even if you need to deal with some ugly nested loops and function calls to do it.

wirthjason 5y ago
This! I was doing some work with a colleague and he was showing off some bash knowledge. I know a bit but my experience is limited since my last job was a Windows a shop. We did a bunch of stuff with “xargs”. He said it was the one misunderstood command. One of the cool things was the ability to parallelize the work with a simple -P flag. You do a find, make sure to use the -print0 flag, pipe it into xargs and use the -0 option then run a command over all the files. If you add -P it magically becomes parallel.
- throwaway0a5e 5y ago
  xargs and awk are two commands I really regret using as little as I do.
  - ZephyrP 5y ago
    I know awk (well, gawk) pretty well and I still regret not having just learned perl.
- brokenmachine 5y ago
  I really hate the way there's no standard flags, so you have to remember that find is -print0 while xargs is -0 and something else might be -null. I spend half my time trying to find the right arguments and the whole time wishing I just bit the bullet at the start and used a real programming language. And god forbid if a filename might have a quote character or a space in it. Then you have to think 5x as hard about what you're doing.
stinos 5y ago
While I agree that arrays are usually not the thing you want in bash, in the end to me this just feels a bit like having to adapt the job to the tool instead of being able to select the right tool for the job. Both of these principles have their place of course, but having to tell people something as common as an array is not really available in this widely used environment is like telling a carpenter to avoid nails or glue all together because this particular workshop only uses screws and an non-electric screwdriver. Perhaps not the most appropriate metaphore, but you get the point: mistakes will be made and time will be wasted. Because 'formatted stream of data' really means 'any tool can output a different arbitrarily formatted stream so if you need a field it is up to you to figure out how, every single time again because no-one can remember this for all possible tools anyway'.
smellf 5y ago
Agreed! I love bash and use it all the time, but if some solution gets to the point of needing actual data structures, that's when you know it's time to move to a real programming language.

wirthjason 5y ago

This! I was doing some work with a colleague and he was showing off some bash knowledge. I know a bit but my experience is limited since my last job was a Windows a shop. We did a bunch of stuff with “xargs”. He said it was the one misunderstood command. One of the cool things was the ability to parallelize the work with a simple -P flag. You do a find, make sure to use the -print0 flag, pipe it into xargs and use the -0 option then run a command over all the files. If you add -P it magically becomes parallel.

throwaway0a5e 5y ago
xargs and awk are two commands I really regret using as little as I do.
- ZephyrP 5y ago
  I know awk (well, gawk) pretty well and I still regret not having just learned perl.
brokenmachine 5y ago
I really hate the way there's no standard flags, so you have to remember that find is -print0 while xargs is -0 and something else might be -null. I spend half my time trying to find the right arguments and the whole time wishing I just bit the bullet at the start and used a real programming language. And god forbid if a filename might have a quote character or a space in it. Then you have to think 5x as hard about what you're doing.

stinos 5y ago

While I agree that arrays are usually not the thing you want in bash, in the end to me this just feels a bit like having to adapt the job to the tool instead of being able to select the right tool for the job. Both of these principles have their place of course, but having to tell people something as common as an array is not really available in this widely used environment is like telling a carpenter to avoid nails or glue all together because this particular workshop only uses screws and an non-electric screwdriver. Perhaps not the most appropriate metaphore, but you get the point: mistakes will be made and time will be wasted. Because 'formatted stream of data' really means 'any tool can output a different arbitrarily formatted stream so if you need a field it is up to you to figure out how, every single time again because no-one can remember this for all possible tools anyway'.

smellf 5y ago

Agreed! I love bash and use it all the time, but if some solution gets to the point of needing actual data structures, that's when you know it's time to move to a real programming language.