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>I would recommend learning and using sh unless you really need Bash. I don't buy this argument. Ok, it's a standard, but sometimes it's a pain-in-the-hole sta

>I would recommend learning and using sh unless you really need Bash. I don't buy this argument. Ok, it's a standard, but sometimes it's a pain-in-the-hole standard. Bash augmentations lessen some of the pains, and it's just nicer. The only situation is if you're using busybox in a very limited system or you reeeeeally need your script to run on many difference unices, which let's be honest, is not that common nowadays.

JdeBP 3y ago
All of this was covered in great detail in the 2000s, when Debian and Ubuntu switched /bin/sh to the Debian Almquist shell, which was basically POSIX-only with some 3 things that Debian people simply couldn't live without, and encouraged system scripts to use it. If you weren't around then, go and read the discussions. They're mostly still available, and they cover some important stuff that straw man counterarguments regularly miss. The Debian people were concerned, for starters, with how much time the Bourne Again shell spent, at process initialization, setting up things for extensions and interactive features that were never employed in non-interactive "sh" mode; a significant cause for concern given how much of the system was executable shell scripts.
- jmclnx 3y ago
  >with some 3 things that Debian people simply couldn't live without Curious, what are the 3 things ? But yes, people should always use sh (or ksh) for scripting as opposed to bash, why, it is far more portable to other systems.
  - JdeBP 3y ago
    Originally it was echo -n, local, and logical operators in test. There was just so much Debian stuff that assumed these. * https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=294962 https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=294962 They've added 2 more since. * https://www.debian.org/doc/debian-policy/ch-files.html#scripts https://www.debian.org/doc/debian-policy/ch-files.html#scrip... Strictly speaking, there are other differences between the Debian Almquist shell and a truly SUS conformant sh. * https://unix.stackexchange.com/q/697007/5132 https://unix.stackexchange.com/q/697007/5132 But the aforementioned are what Debian people explicitly wanted and couldn't live without. Note that the StackExchange answer is a comparison of a 2022 dash to a 2017 standard, neither of which existed at the time. Debian Policy, the Debian Almquist shell, and the POSIX standard have all been revised since then.
kaba0 3y ago
> Bash augmentations lessen some of the pains, and it's just nicer Both sh and bash are terrible, ugly hacks. Anything that requires more than 3 lines of them (including the #! line) should be written in a proper scripting language. Though I do agree that cross-platformity to that level is rarely meaningful, and so things like python are just as likely available/can be made available.
- ndsipa_pomu 3y ago
  Which version of python though?
  - kaba0 3y ago
    Add a flake.nix file and you get completely reproducible program versions if you really want. But I know that you meant it as a rhetoric, so my non-rhetorical answer would be that python3 is almost universally available on distros that are not minified deliberately (containers).
    - ndsipa_pomu 3y ago
      > python3 is almost universally available on distros that are not minified deliberately (containers) Writing control scripts for use inside containers is currently my biggest application of BASH scripts. What makes BASH (or other shells) handy is the lack of supporting files that are needed - just copy in the script and you're ready to go.
      - time0ut 3y ago
        I was going to say something similar. I try to avoid adding anything to my final images. Each extra dependency is something else to update, more surface areas for attacks, another thing to justify, etc. Much rather just use the slimmest base and the tools already available.
  - paulddraper 3y ago
    3 Which version of Bash?
blueflow 3y ago
> is not that common nowadays Due to docker, minimalistic Linux'es have been more common, including trimmed-down versions of distros that would otherwise feature bash.
- synergy20 3y ago
  bash is rarely the focus though, it really just costs 1MB in storage, which is nothing comparing to python,etc.
  - paulddraper 3y ago
    Nonetheless Bash is very frequently omitted in my experience.
  - 9dev 3y ago
    Well, usually I have to decide between „do I look up the magic incantation to install bash in this container and risk fucking up the layer cache“ or „do I modify this script to not use bash-isms and feel like I’m a Unix purist in the process“, and the answer is the latter usually
  - foobarian 3y ago
    Just 1MB? That's most of a double-density floppy disk!
synergy20 3y ago
I do small embedded systems with busybox, even that I can squeeze in bash when I need that, it's about 1MB in size and gives a lot more than busybox's sh. Another option is Lua which is also great.
yyyk 3y ago
If you wish require some users to install an interpreter, you might as well go for Korn or a real programming language. If you want to use something that's portable and installed everywhere, that's POSIX sh (or at most dash-like level). Bash is in the poor middle which isn't good enough for either side, unless you really know what's your target and don't care about elsewhere.

JdeBP 3y ago

All of this was covered in great detail in the 2000s, when Debian and Ubuntu switched /bin/sh to the Debian Almquist shell, which was basically POSIX-only with some 3 things that Debian people simply couldn't live without, and encouraged system scripts to use it. If you weren't around then, go and read the discussions. They're mostly still available, and they cover some important stuff that straw man counterarguments regularly miss. The Debian people were concerned, for starters, with how much time the Bourne Again shell spent, at process initialization, setting up things for extensions and interactive features that were never employed in non-interactive "sh" mode; a significant cause for concern given how much of the system was executable shell scripts.

jmclnx 3y ago
>with some 3 things that Debian people simply couldn't live without Curious, what are the 3 things ? But yes, people should always use sh (or ksh) for scripting as opposed to bash, why, it is far more portable to other systems.
- JdeBP 3y ago
  Originally it was echo -n, local, and logical operators in test. There was just so much Debian stuff that assumed these. * https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=294962 https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=294962 They've added 2 more since. * https://www.debian.org/doc/debian-policy/ch-files.html#scripts https://www.debian.org/doc/debian-policy/ch-files.html#scrip... Strictly speaking, there are other differences between the Debian Almquist shell and a truly SUS conformant sh. * https://unix.stackexchange.com/q/697007/5132 https://unix.stackexchange.com/q/697007/5132 But the aforementioned are what Debian people explicitly wanted and couldn't live without. Note that the StackExchange answer is a comparison of a 2022 dash to a 2017 standard, neither of which existed at the time. Debian Policy, the Debian Almquist shell, and the POSIX standard have all been revised since then.

kaba0 3y ago

> Bash augmentations lessen some of the pains, and it's just nicer Both sh and bash are terrible, ugly hacks. Anything that requires more than 3 lines of them (including the #! line) should be written in a proper scripting language. Though I do agree that cross-platformity to that level is rarely meaningful, and so things like python are just as likely available/can be made available.

ndsipa_pomu 3y ago
Which version of python though?
- kaba0 3y ago
  Add a flake.nix file and you get completely reproducible program versions if you really want. But I know that you meant it as a rhetoric, so my non-rhetorical answer would be that python3 is almost universally available on distros that are not minified deliberately (containers).
  - ndsipa_pomu 3y ago
    > python3 is almost universally available on distros that are not minified deliberately (containers) Writing control scripts for use inside containers is currently my biggest application of BASH scripts. What makes BASH (or other shells) handy is the lack of supporting files that are needed - just copy in the script and you're ready to go.
    - time0ut 3y ago
      I was going to say something similar. I try to avoid adding anything to my final images. Each extra dependency is something else to update, more surface areas for attacks, another thing to justify, etc. Much rather just use the slimmest base and the tools already available.
- paulddraper 3y ago
  3 Which version of Bash?

blueflow 3y ago

> is not that common nowadays Due to docker, minimalistic Linux'es have been more common, including trimmed-down versions of distros that would otherwise feature bash.

synergy20 3y ago
bash is rarely the focus though, it really just costs 1MB in storage, which is nothing comparing to python,etc.
- paulddraper 3y ago
  Nonetheless Bash is very frequently omitted in my experience.
- 9dev 3y ago
  Well, usually I have to decide between „do I look up the magic incantation to install bash in this container and risk fucking up the layer cache“ or „do I modify this script to not use bash-isms and feel like I’m a Unix purist in the process“, and the answer is the latter usually
- foobarian 3y ago
  Just 1MB? That's most of a double-density floppy disk!

synergy20 3y ago

I do small embedded systems with busybox, even that I can squeeze in bash when I need that, it's about 1MB in size and gives a lot more than busybox's sh. Another option is Lua which is also great.

yyyk 3y ago

If you wish require some users to install an interpreter, you might as well go for Korn or a real programming language. If you want to use something that's portable and installed everywhere, that's POSIX sh (or at most dash-like level). Bash is in the poor middle which isn't good enough for either side, unless you really know what's your target and don't care about elsewhere.