Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Bash code generator for command-line arguments

github.com

Post reply on HN
Print view View original

31–40 of 54 posts

Re: Bash code generator for command-line arguments

#31

Post by macNchz »

bxparks wrote: post #20

I start all my bash scripts from the following template, then modify it as needed. It is not fancy, but I think it supports the lowest common denominator that is compatible with other flag processing systems in all other languages that I am aware of. (In particular, it does not support '--option=opt' but uses '--option opt', which is cross-compatible). I like that it is small, easy to maintain, and avoids external de…

This is handy, thanks! Definitely one of those things I wind up badly/slowly reinventing the boilerplate for every time.

Re: Bash code generator for command-line arguments

#32

Post by Aaronstotle »

jaydecus wrote: post #16
holtalanm wrote: post #15

I'm probably going to get downvoted for this, but: writing bash scripts in general just isn't a fun experience. years ago, i started just writing ruby scripts for execution in the terminal instead of bash, and haven't had any problems with it so far.

A few years ago I would have disagreed, but today I quite enjoy it. What changes my opinion was mostly having a decent IDE configured to deal with the annoying bash syntax errors, and a quicker way to prototype. Though in generqal I always thought Bash scripting to be fun, due to the wide array of programs available that you can directly invoke in your scripts script. The feeling of gluing programs together with pipe…

That last part is why I routinely stick with bash for quick scripts. For example, I usually create boolean values to check for a proper config by using grep or grep -c.

Do you have any recommendations for an IDE to use for Bash scripting?

Re: Bash code generator for command-line arguments

#33

Post by sjburt »

arthur2e5 wrote: post #6

> getopt is discouraged, getopts doesn't support long options Hold up. The only version of getopt with long option support is from util-linux, which fixes all the whitespace issues people were discouraging getopt for. So what's the stated goal of this project again? Heck, you don't even need to write code to detect usage of legacy getopt. It will panic every time you use the new stuff once it sees the option to turn…

Getopt isn't a builtin and the BSD/OSX one is different.

Re: Bash code generator for command-line arguments

#34

Post by kortex »

holtalanm wrote: post #15

I'm probably going to get downvoted for this, but: writing bash scripts in general just isn't a fun experience. years ago, i started just writing ruby scripts for execution in the terminal instead of bash, and haven't had any problems with it so far.

I got bit by a Bash-ism late last night (-ne vs != causing a CI test to silently fail) and that was kind of the last straw for me.

I drive zsh but still use bash scripts a lot cause "portability" and "it's available everywhere" but that argument just doesn't hold up when I'm already in control of most of my stacks and have docker access on pretty much every host I'm in.

I'm forcing myself to use Xonsh more, which despite having all its own quirks, is so much less mental overhead going between Python development. Yeah maybe it's a few more steps (than zero for bash) to provision, but it's worth it.

Re: Bash code generator for command-line arguments

#35

Post by kortex »

Aaronstotle wrote: post #32
jaydecus wrote: post #16

Earlier quoted context omitted.

A few years ago I would have disagreed, but today I quite enjoy it. What changes my opinion was mostly having a decent IDE configured to deal with the annoying bash syntax errors, and a quicker way to prototype. Though in generqal I always thought Bash scripting to be fun, due to the wide array of programs available that you can directly invoke in your scripts script. The feeling of gluing programs together with pipe…

That last part is why I routinely stick with bash for quick scripts. For example, I usually create boolean values to check for a proper config by using grep or grep -c. Do you have any recommendations for an IDE to use for Bash scripting?

Shellcheck (https://www.shellcheck.net/) is essential, with or without IDE.

Pycharm has it built in or as a plugin now too.

Re: Bash code generator for command-line arguments

#36

Post by moonchild »

bxparks wrote: post #20

I start all my bash scripts from the following template, then modify it as needed. It is not fancy, but I think it supports the lowest common denominator that is compatible with other flag processing systems in all other languages that I am aware of. (In particular, it does not support '--option=opt' but uses '--option opt', which is cross-compatible). I like that it is small, easy to maintain, and avoids external de…

I recommend making 'usage' return 0, rather than 1; since asking for help is valid.

(Since you use it both for -h and for unknown options, perhaps make it not exit at all, and make the caller exit with an appropriate code?)

Additionally, you should output the actual executable name (as passed in on $0) rather than hardcoding something. So maybe at the top say 'executable=$0; shift'; replace parseflags.sh with $executable; and replace $1 with $0 in your option parse loop.

Re: Bash code generator for command-line arguments

#37

Post by mturmon »

raziel2p wrote: post #7
usrme wrote: post #3

Quite an impressive project all things considered; definitely something to keep in mind for the next project that inevitably starts out as a simple Bash script. Out of curiosity: if you (the reader) get to a point where you need more complicated and esoteric functionality that Bash can provide, do you still keep hammering at it or turn to a more capable (and readable) language? Just wondering if people are usually wo…

It's a trade-off. Especially if the script contains a lot of pipes and redirection, it's difficult to reproduce with the same elegance in something like Python. My biggest successes have been extracting these parts into very small stand-alone shell scripts which the Python application then invokes, which gives you the best of both worlds. The best example off the top of my head is `mysqldump | sed ... | gzip` with de…

> My biggest successes have been extracting these parts into very small stand-alone shell scripts which the Python application then invokes ...

That's a clever way to go.

Sometimes the other way around works too: taking the most fiddly manipulations (say, date or time intervals) and re-homing them to a small Python script, but leaving the bash intact.

Re: Bash code generator for command-line arguments

#38

Post by kortex »

lysium wrote: post #4
usrme wrote: post #3

Quite an impressive project all things considered; definitely something to keep in mind for the next project that inevitably starts out as a simple Bash script. Out of curiosity: if you (the reader) get to a point where you need more complicated and esoteric functionality that Bash can provide, do you still keep hammering at it or turn to a more capable (and readable) language? Just wondering if people are usually wo…

I've tried that path with little success. Usually, arg parsing makes me try some other language (perl, python) but other things got complicated there, mostly running other processes, capturing their exit status, pipe-ing their output etc. In the end, it was easier to hammer onto bash. Also, there are great linters for bash scripts, so things work out.

I've been in a similar boat, yet despite as my experience with it grows, bash just wears on me. Everything feels like a hack. Sure, piping is easy, but if statements are atrocious.

Starting to get into Xonsh. Still a learning curve, cause it's neither bash nor python, but it's really refreshing.

Re: Bash code generator for command-line arguments

#39

Post by kortex »

raziel2p wrote: post #7
usrme wrote: post #3

Quite an impressive project all things considered; definitely something to keep in mind for the next project that inevitably starts out as a simple Bash script. Out of curiosity: if you (the reader) get to a point where you need more complicated and esoteric functionality that Bash can provide, do you still keep hammering at it or turn to a more capable (and readable) language? Just wondering if people are usually wo…

It's a trade-off. Especially if the script contains a lot of pipes and redirection, it's difficult to reproduce with the same elegance in something like Python. My biggest successes have been extracting these parts into very small stand-alone shell scripts which the Python application then invokes, which gives you the best of both worlds. The best example off the top of my head is `mysqldump | sed ... | gzip` with de…

There is also plumbum for more ergonomic pipelines in python:

https://pypi.org/project/plumbum/

Re: Bash code generator for command-line arguments

#40

Post by dotancohen »

jonahx wrote: post #30
holtalanm wrote: post #15

I'm probably going to get downvoted for this, but: writing bash scripts in general just isn't a fun experience. years ago, i started just writing ruby scripts for execution in the terminal instead of bash, and haven't had any problems with it so far.

Ruby is definitely a better tool for this but there are situations where it's not available but bash is. That portability is really the only advantage.

Now that Python 2 is deprecated, I think that settling on Python for scripts is the happy medium. It is available in all but the most stripped-down linux builds, and those are commonly seen today only in docker images or hardware. And adding it to e.g. Alpine is trivial.
Post reply on HN