Script to update rust nightly and recompile all of your projects

update-rust.sh

#!/usr/bin/env bash

set -eu -o pipefail

# --force to reinstall in case we updated NixOS and GC'ed old paths, but no new nightly is available
rustup update --force
rustup default nightly

# List most-used projects first so that they're available sooner
projects=(
	~/code/rust/rust-analyzer
	~/code/rust/something
  ~/code/rust/else
)

for p in "${projects[@]}"; do
	echo $p
	cd "$p" || continue
	# Remove files older than 2 days from target/ because otherwise it grows
	# to many GB as target/*/deps has builds for each Rust release
	find target -type f -mtime +2 -delete || true
	cargo build --release || true
	if [[ $p = ~/code/rust/rust-analyzer ]]; then
		# Custom install procedure for rust-analyzer
		cp -alf ./target/release/rust-analyzer ~/bin/_rust-analyzer
	else
		cargo build || true
		cargo test || true
	fi
done

To run it nightly on NixOS, use configuration

{
  systemd.services.update-rust = {
    description = "Update Rust and rebuild projects";
    serviceConfig = {
      Type = "oneshot";
      User = "USERNAME";
      Environment = "PATH=/home/USERNAME/bin:/run/current-system/sw/bin";
    };
    # 04:00 PST is 12:00 UTC
    startAt = "12:00";
    script = ''
      update-rust
    '';
  };
}