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Show HN: Using Rust to write shell-script like tasks
21–30 of 83 posts
Re: Show HN: Using Rust to write shell-script like tasks
#22Earlier quoted context omitted.
It’s inside a .rs file so I don’t see how it’s not unsafe in the Rust sense. Maybe when I drew parallels with the “unsafe” block wasn’t fair but safety isn’t just about memory safety. Any seasoned developer will tell you that writing safe software is a multi-paradigm problem. The MVC point is that by having shell scripts separated out as their own .sh file means they draw attention to themselves when auditing code. I…
> It’s inside a .rs file so I don’t see how it’s not unsafe in the Rust sense. Maybe when I drew parallels with the “unsafe” block wasn’t fair but safety isn’t just about memory safety. Any seasoned developer will tell you that writing safe software is a multi-paradigm problem. If I call a function that can result in an error condition, and I correctly handle the error condition, my code is not "unsafe". So while yes…
The subprocess API is without system calls? Otherwise it calls into heretic C code.
Of course Rust itself is not "safe" either:
Re: Show HN: Using Rust to write shell-script like tasks
#23If this is a fun proof of concept, it's nice.
If somebody uses this in an actual system, it's terrifying.
edit oh, Rust is now a thing where even the bad ideas need to be praised without caveats. Gotcha
Re: Show HN: Using Rust to write shell-script like tasks
#24> A lot developers just choose shell(sh, bash, ...) scripts for such tasks, > by using to redirect output and '|' to pipe outputs. > In my experience, this is the only good parts of shell script. If you try to use shell as a general purpose programming language, of course it sucks. If you treat shell as a DSL for files and streams, nothing can beat it. Shell is amazing. I'm sceptical a bunch of Rust macros can beat s…
> If you treat shell as a DSL for files and streams, nothing can beat it. Shell is amazing.
On the other hand, wouldn’t you just define anything that beats it also a shell? In my opinion, Fish beats Bash and Zsh in this area, and I would definitely call it a shell even though it’s not a POSIX-compatible shell. A more extreme example would be PowerShell (I’m not a fan but some people love it).
Where would you draw the line between a “shell” and an “interpreted scripting language that beats POSIX shells on dealing with files and streams”?
Re: Show HN: Using Rust to write shell-script like tasks
#25Earlier quoted context omitted.
> It’s inside a .rs file so I don’t see how it’s not unsafe in the Rust sense. Maybe when I drew parallels with the “unsafe” block wasn’t fair but safety isn’t just about memory safety. Any seasoned developer will tell you that writing safe software is a multi-paradigm problem. If I call a function that can result in an error condition, and I correctly handle the error condition, my code is not "unsafe". So while yes…
> So while yes, calling "rm -rf /" is dangerous, it is no more dangerous when done in rust than anywhere else, since you're just calling a subprocess, and the subprocess API is a safe API. There's nothing "unsafe" (in the rust sense, meaning type- or memory-unsafe) about doing so. The point is that code doesn't belong in Rust to begin with! > Yes, but if you have to shell out at some point, the difference between cal…
> The point is that code doesn't belong in Rust to begin with!
I'll reiterate: it is often safer to embed short snippets of bash into other languages than to invert control and call out to other languages from bash. By calling out to bash, you do the majority of your work in better languages.
> No it isn't. Code auditing and vetting has been a thing for years. Say you have a CI pipeline that hooked into Shellcheck to validate your .sh files for errors, that same pipeline wouldn't vet any pseudo shell code inlined in Rust.
You're making a rather particular set of assumptions there.
> Not all, only the concerns you've cherrypicked.
The three you originally mentioned...
Re: Show HN: Using Rust to write shell-script like tasks
#26I am not a huge fan of copying the shell language wholesale and wrapping inside a macro. Since macros can execute arbitrary code, this makes me feel uneasy that the strings are just executed within a shell context, with all the appropriate, bug-prone, expansion done by the shell. Seeing "ls /nofile || true;" makes me worry that "||" is actually passed to the shell wholesale. There's also no transparency about how the…
Since macros can execute arbitrary code, this makes me feel uneasy that the strings are just executed within a shell context, with all the appropriate, bug-prone, expansion done by the shell.
Its a shame you didn't bother to look at the source code before criticizing. Someone put a lot of work into this library and its actually pretty cool.
The package parses the code in the macros [1] and then calls 'std:Process::Command' [2] which, I believe, does not execute a subshell by default.
[1] https://github.com/rust-shell-script/rust_cmd_lib/blob/maste...
[2] https://github.com/rust-shell-script/rust_cmd_lib/blob/maste...
Re: Show HN: Using Rust to write shell-script like tasks
#27This reminds me of the python version of this called xonsh https://xon.sh/
I really like the idea, but it was missing some simple features that bash had. I can't recall them right now but after an hour of trying to convert a simple bash script, I gave up. That was a year ago. Maybe things changed.
I'll give this and xonsh a go again because I just really dislike bash. Thanks for the project!
Re: Show HN: Using Rust to write shell-script like tasks
#28My god, this super useful when you have a mix o shell commands and processing text output from them. Bash isn’t particularly easy to work with parsing non-trivial strings in a readable way (I’m looking at you awk)
This is why Perl and regular expressions have been so popular on Unix and Linux systems for the past 30 years or so.
Python and Ruby are also very handy for these kinds of tasks.
People joke about regular expressions being another problem to solve, but they really are an elegant solution to handle a LARGE portion of text processing needs.
Re: Show HN: Using Rust to write shell-script like tasks
#29I really don't see the point of these. Probably just need to explore available tools a bit more.
Re: Show HN: Using Rust to write shell-script like tasks
#30I am not a huge fan of copying the shell language wholesale and wrapping inside a macro. Since macros can execute arbitrary code, this makes me feel uneasy that the strings are just executed within a shell context, with all the appropriate, bug-prone, expansion done by the shell. Seeing "ls /nofile || true;" makes me worry that "||" is actually passed to the shell wholesale. There's also no transparency about how the…
I agree, this is a misguided idea. The whole point of not using Bash is that you don't have to use it's terrible design and syntax surely?
This only seems to use the good parts of the shell, easy piping and redirection, while dropping the language for logic.