Add a "single column" mode for `rustup toolchain list` and friends

[tgross35]

Problem you are trying to solve

I update nightly frequently and always wind up with a lot of toolchains that I am unlikely to use again:

$ rustup show
installed toolchains
--------------------

stable-x86_64-unknown-linux-gnu
nightly-2023-04-29-x86_64-unknown-linux-gnu
nightly-2023-06-15-x86_64-unknown-linux-gnu
nightly-2023-06-19-x86_64-unknown-linux-gnu
nightly-2023-07-14-x86_64-unknown-linux-gnu
nightly-2023-07-22-x86_64-unknown-linux-gnu
nightly-2023-07-28-x86_64-unknown-linux-gnu
nightly-2023-08-08-x86_64-unknown-linux-gnu
nightly-2023-08-24-x86_64-unknown-linux-gnu
1.60-x86_64-unknown-linux-gnu
1.63-x86_64-unknown-linux-gnu
stage1
stage2
1.68.2-x86_64-unknown-linux-gnu
1.71.0-x86_64-unknown-linux-gnu
1.71.1-x86_64-unknown-linux-gnu

active toolchain
----------------

nightly-x86_64-unknown-linux-gnu (default)
rustc 1.75.0-nightly (e5cfc5547 2023-10-28)

There is no easy way to remove all toolchains matching a pattern

Solution you'd like

Allow * as a wildcard for removal and other relevant commands so that this works:

$ rustup toolchain remove nightly-2023-*
info: no toolchain installed for 'nightly-2023-*'

Notes

rustup 1.26.0 (5af9b94 2023-04-05)

[rami3l]

@tgross35 Thanks a lot for filing this issue!

This is also one of the pain points that I often encounter when using rustup and elan, so I'm quite willing to address it. However, due to how rustup resolves toolchain names ¹, this might not be a simple fix.

Furthermore, one might argue that a one-line script like the following will suffice:

rustup toolchain list | cut -d ' ' -f1 | grep nightly-2023- | xargs rustup uninstall

@rbtcollins @djc What do you think?

Footnotes

1. In case you don't know, you can do something like rustup toolchain uninstall 1.39-x86_64. ↩

[rbtcollins]

the (default) in rustup toolchain list makes that harder to work with.

I wonder if dropping that default, making the list more API-like, adding 'rustup toolchain default' or something similar, would make this nicer.

I'm a bit skeptical of rustup doing its own globbing here.

[rami3l]

@rbtcollins Okay, I think it would be better to find a workaround then.

IMHO it would be nice if we can leave the output as-is and add a new flag specifically to give simple outputs for non-interactive uses.
For instance, this is what we'll get if we borrow the "single-column mode" (written as -1) from brew:

> rustup toolchain list
stable-aarch64-apple-darwin (default)
nightly-aarch64-apple-darwin

> rustup toolchain list -1
stable-aarch64-apple-darwin
nightly-aarch64-apple-darwin

I don't quite like -1 though, and would possibly call it --simple/-s.
Or we can add a new --quiet for this purpose.

Anyway, this change should probably be mirrored to rustup target list and other similar commands.

[djc]

I like -q/--quiet for this!

[rami3l]

I'll find some time to implement this --quiet thing then. Claim.

[rami3l]

Now that the output format is being changed in #3225, I think we should wait a bit before implementing this.