7 ms·

I think bash has a lot of gotchas due to its original purpose, and it's definitely more error-prone to write bash scripts than to e.g. write Python scripts, so

by vore 5y ago

I think bash has a lot of gotchas due to its original purpose, and it's definitely more error-prone to write bash scripts than to e.g. write Python scripts, so that should be a consideration. Ideally we should all try to more programming languages that are harder for us to shoot ourselves in the foot with, rather than easier ;-)

marginalia_nu 5y ago
I think considering the purpose of the language, it does rather well. It's really easy to spawn and pipe processes, far more so than in almost any alternatives. Like it's so easy that it's easy to forget that this is like a 5-10 line overhead dance to launch and read from a process in most languages. The problem usually come when you attempt to use it for nontrivial programming. But that just not what it's for, any more than the difficulty in building an OS kernel is a legitimate complaint against PHP.
- vore 5y ago
  I think this is what the post you were replying to is saying.
- chasil 5y ago
  Stephen Borne famously disliked C, and much preferred Algol. This is important to know in the context of what you are saying. The Algol structures in the Borne shell are the most incongruous parts of UNIX. https://research.swtch.com/shmacro https://research.swtch.com/shmacro
chasil 5y ago
I will just leave this here. "I am a strong believer that Bourne-derived languages are extremely bad, on the same order of badness as Perl, for programming, and consider programming sh for any purpose other than as a super-portable, lowest-common-denominator platform for build or bootstrap scripts and the like, as an extremely misguided endeavor. As such you won’t see me spending many words on extensions particular to ksh, Bash, or whatever other shells may be popular." http://www.etalabs.net/sh_tricks.html http://www.etalabs.net/sh_tricks.html
- marginalia_nu 5y ago
  I think it's easy to sort of gloss over how good shell scripts are at the sort of things they actually are good at. Consider this: for f in *png; do convert $f $(echo $f | sed 's/png$/webp/'); done This is like at least a screen of code in in most languages, you get that sinking feeling where you need to fork a process and deal with its lifecycle and deal with some standard library to list files and don't forget to close the file handle for the directory and god forgive if you run a program with actual output then you need to read from a pipe. Like, geesh, do I have to write a whole program to convert a few files? In a shell, it's just something you type up because you needed to convert a few files. Don't get me wrong, shell scripts are extremely bad at most things involving non-trivial branches, long-lived state, really most things other languages are good at, but man are they ever good at some things most programming languages are bad at.
  - leephillips 5y ago
    lee@sp3tmp1:ls *.png 'a b.png' c.png lee@sp3tmp1:for f in *png; do convert $f $(echo $f | sed 's/png$/web'); done convert-im6.q16: unable to open image `a': No such file or directory @ error/blob.c/OpenBlob/2924. convert-im6.q16: no decode delegate for this image format `' @ error/constitute.c/ReadImage/575. convert-im6.q16: unable to open image `b.png': No such file or directory @ error/blob.c/OpenBlob/2924. convert-im6.q16: unable to open image `b.png': No such file or directory @ error/blob.c/OpenBlob/2924. convert-im6.q16: no decode delegate for this image format `' @ error/constitute.c/ReadImage/575. convert-im6.q16: no images defined `b.webp' @ error/convert.c/ConvertImageCommand/3229. [etc.] I think you could be making a more complicated point.
  - _kst_ 5y ago
    Better: for f in *.png; do convert "$f" "${f/%.png/.webp}" ; done Quoting the arguments lets it correctly handle file names with funny characters, including spaces. Using the `${parameter/pattern/string}` parameter substitution means the shell does all the work itself without invoking an external command (other than convert, of course). The '%' in the parameter substitution requires the pattern to match at the end, so "foo.png.png" becomes "foo.png.webp" and not "foo.webp.png" -- an unlikely corner case, but you might as well do it right. ("foo.png.blah" doesn't match "*.png" in the first place.) For elaborate commands like this, I typically run it once with an "echo" inserted ("echo convert ..."), confirm that the resulting commands make sense, and then hit up-arrow to edit the command and delete the echo. https://www.gnu.org/software/bash/manual/html_node/Shell-Parameter-Expansion.html https://www.gnu.org/software/bash/manual/html_node/Shell-Par...
suifbwish 5y ago
By that logic shouldn’t we also stop using programming languages that aren’t threadsafe? Segfaulting could be prevented if C++ wasn’t so esoteric.

by vore 5y ago

marginalia_nu 5y ago

I think considering the purpose of the language, it does rather well. It's really easy to spawn and pipe processes, far more so than in almost any alternatives. Like it's so easy that it's easy to forget that this is like a 5-10 line overhead dance to launch and read from a process in most languages. The problem usually come when you attempt to use it for nontrivial programming. But that just not what it's for, any more than the difficulty in building an OS kernel is a legitimate complaint against PHP.

vore 5y ago
I think this is what the post you were replying to is saying.
chasil 5y ago
Stephen Borne famously disliked C, and much preferred Algol. This is important to know in the context of what you are saying. The Algol structures in the Borne shell are the most incongruous parts of UNIX. https://research.swtch.com/shmacro https://research.swtch.com/shmacro

chasil 5y ago

I will just leave this here. "I am a strong believer that Bourne-derived languages are extremely bad, on the same order of badness as Perl, for programming, and consider programming sh for any purpose other than as a super-portable, lowest-common-denominator platform for build or bootstrap scripts and the like, as an extremely misguided endeavor. As such you won’t see me spending many words on extensions particular to ksh, Bash, or whatever other shells may be popular." http://www.etalabs.net/sh_tricks.html http://www.etalabs.net/sh_tricks.html

marginalia_nu 5y ago
I think it's easy to sort of gloss over how good shell scripts are at the sort of things they actually are good at. Consider this: for f in *png; do convert $f $(echo $f | sed 's/png$/webp/'); done This is like at least a screen of code in in most languages, you get that sinking feeling where you need to fork a process and deal with its lifecycle and deal with some standard library to list files and don't forget to close the file handle for the directory and god forgive if you run a program with actual output then you need to read from a pipe. Like, geesh, do I have to write a whole program to convert a few files? In a shell, it's just something you type up because you needed to convert a few files. Don't get me wrong, shell scripts are extremely bad at most things involving non-trivial branches, long-lived state, really most things other languages are good at, but man are they ever good at some things most programming languages are bad at.
- leephillips 5y ago
  lee@sp3tmp1:ls *.png 'a b.png' c.png lee@sp3tmp1:for f in *png; do convert $f $(echo $f | sed 's/png$/web'); done convert-im6.q16: unable to open image `a': No such file or directory @ error/blob.c/OpenBlob/2924. convert-im6.q16: no decode delegate for this image format `' @ error/constitute.c/ReadImage/575. convert-im6.q16: unable to open image `b.png': No such file or directory @ error/blob.c/OpenBlob/2924. convert-im6.q16: unable to open image `b.png': No such file or directory @ error/blob.c/OpenBlob/2924. convert-im6.q16: no decode delegate for this image format `' @ error/constitute.c/ReadImage/575. convert-im6.q16: no images defined `b.webp' @ error/convert.c/ConvertImageCommand/3229. [etc.] I think you could be making a more complicated point.
- _kst_ 5y ago
  Better: for f in *.png; do convert "$f" "${f/%.png/.webp}" ; done Quoting the arguments lets it correctly handle file names with funny characters, including spaces. Using the `${parameter/pattern/string}` parameter substitution means the shell does all the work itself without invoking an external command (other than convert, of course). The '%' in the parameter substitution requires the pattern to match at the end, so "foo.png.png" becomes "foo.png.webp" and not "foo.webp.png" -- an unlikely corner case, but you might as well do it right. ("foo.png.blah" doesn't match "*.png" in the first place.) For elaborate commands like this, I typically run it once with an "echo" inserted ("echo convert ..."), confirm that the resulting commands make sense, and then hit up-arrow to edit the command and delete the echo. https://www.gnu.org/software/bash/manual/html_node/Shell-Parameter-Expansion.html https://www.gnu.org/software/bash/manual/html_node/Shell-Par...

suifbwish 5y ago

By that logic shouldn’t we also stop using programming languages that aren’t threadsafe? Segfaulting could be prevented if C++ wasn’t so esoteric.