this post was submitted on 13 Mar 2025
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Am in the only one who cringes at install instructions that require piping some curl output into bash? (programming.dev)
submitted 1 week ago by cschreib@programming.dev to c/linux@programming.dev
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curl https://some-url/ | sh

I see this all over the place nowadays, even in communities that, I would think, should be security conscious. How is that safe? What's stopping the downloaded script from wiping my home directory? If you use this, how can you feel comfortable?

I understand that we have the same problems with the installed application, even if it was downloaded and installed manually. But I feel the bar for making a mistake in a shell script is much lower than in whatever language the main application is written. Don't we have something better than "sh" for this? Something with less power to do harm?

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[–] lemmeBe@sh.itjust.works 0 points 1 week ago (1 children)

I think safer approach is to:

  1. Download the script first, review its contents, and then execute.
  2. Ensure the URL uses HTTPS to reduce the risk of man-in-the-middle attacks
[–] easily3667@lemmus.org -1 points 1 week ago* (last edited 1 week ago)

Ah yes for all of the bash experts who understand what they are reading.

[–] knexcar@lemmy.world 0 points 1 week ago (1 children)

What does curl even do? Unstraighten? Seems like any other command I’d blindly paste from an internet thread into a terminal window to try to get something on Linux to work.

[–] Irelephant@lemm.ee 1 points 1 week ago

curl sends requests, curl lemmy.world would return the html of lemmy.worlds homepage. piping it into bash means that you are fetching a shell script, and running it.

[–] zygo_histo_morpheus@programming.dev 0 points 1 week ago (1 children)

You have the option of piping it into a file instead, inspecting that file for yourself and then running it, or running it in some sandboxed environment. Ultimately though, if you are downloading software over the internet you have to place a certain amount of trust in the person your downloading the software from. Even if you're absolutely sure that the download script doesn't wipe your home directory, you're going to have to run the program at some point and it could just as easily wipe your home directory at that point instead.

[–] rah@feddit.uk 0 points 1 week ago* (last edited 1 week ago) (1 children)

You have the option of piping it into a file instead, inspecting that file for yourself and then running it, or running it in some sandboxed environment.

That's not what projects recommend though. Many recommend piping the output of an HTTP transfer over the public Internet directly into a shell interpreter. Even just

curl https://... > install.sh; sh install.sh

would be one step up. The absolute minimum recommendation IMHO should be

curl https://... > install.sh; less install.sh; sh install.sh

but this is still problematic.

Ultimately, installing software is a labourious process which requires care, attention and the informed use of GPG. It shouldn't be simplified for convenience.

Also, FYI, the word "option" implies that I'm somehow restricted to a limited set of options in how I can use my GNU/Linux computer which is not the case.

[–] gaylord_fartmaster@lemmy.world 0 points 1 week ago (1 children)

Showing people that are running curl piped to bash the script they are about to run doesn't really accomplish anything. If they can read bash and want to review the script then they can by just opening the URL, and the people that aren't doing that don't care what's in the script, so why waste their time with it?

Do you think most users installing software from the AUR are actually reading the pkgbuilds? I'd guess it's a pretty small percentage that do.

[–] rah@feddit.uk 0 points 1 week ago* (last edited 1 week ago) (1 children)

Showing people that are running curl piped to bash the script they are about to run doesn't really accomplish anything. If they can read bash and want to review the script then they can by just opening the URL

What it accomplishes is providing the instructions (i.e. an easily copy-and-pastable terminal command) for people to do exactly that.

[–] gaylord_fartmaster@lemmy.world 0 points 1 week ago (1 children)

If you can't review a bash script before running it without having an unnecessarily complex one-liner provided to you to do so, then it doesn't matter because you aren't going to be able to adequately review a bash script anyway.

[–] rah@feddit.uk 0 points 1 week ago (1 children)

If you can't review a bash script before running it without having an unnecessarily complex one-liner provided to you

Providing an easily copy-and-pastable one-liner does not imply that the reader could not themselves write such a one-liner.

Having the capacity to write one's own commands doesn't imply that there is no value in having a command provided.

unnecessarily complex

LOL

[–] gaylord_fartmaster@lemmy.world 0 points 1 week ago (1 children)

I don't think you realize that if your goal is to have a simple install method anyone can use, even redirecting the output to install.sh like in your examples is enough added complexity to make it not work in some cases. Again, those are not made for people that know bash.

[–] rah@feddit.uk -1 points 1 week ago* (last edited 1 week ago)

even redirecting the output to install.sh like in your examples is enough added complexity to make it not work in some cases

You can't have an install method that works in all cases.

if your goal is to have a simple install method anyone can use

Similarly, you can't have an install method anyone can use.