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proto v0.26 (rc) - Release candidate available for testing!

· 3 min read
Miles Johnson
Founder, developer

We've got a very special release candidate that we'd love to stress test before an official release!

proto at its core is a version manager, which means like most version managers, it relies on a concept known as shims. Shims are lightweight executable scripts that act like a proxy to the underlying binary, and are useful for proto to intercept executions and inject custom functionality, like our dynamic version detection.

On Unix machines, we relied on Bash scripts for shims, which worked rather well. However, on Windows, we relied on PowerShell scripts (.ps1), batch/cmd scripts (.cmd), and Bash scripts, all with differing levels of functionality, and each serving a separate purpose. Windows support did not work well.

What didn't work?

When using shims, you must ensure that all the following scenarios work well: piping data/commands, redirection, stdin prompts, interactivity, signal handling, exit code bubbling, so on and so forth. Bash solves a lot of this for us, but Windows does not have a native Bash shell, and thus we had to rely on other scripting languages. The .cmd files barely supported any of this, and the .ps1 files were a bit better, but still not great.

For the most part, executing a shim as-is and doing basic work was fine, but once you needed a complex scenario (like above), it broke down pretty quickly. It was also further exacerbated when dealing with nested shim exections, for example, npm calls node under the hood. The parent shim may be executed with .ps1 but the child may be .cmd, and these do not play well together.

The other problem on Windows is that scripts are not true executables, and are not easily located on PATH (excluding .cmd files).

What's new?

To combat all of these problems, we needed a truly native solution, and that's exactly what we did. We wrote our own Rust based executable, that will replace all of the custom shim scripts, and can properly handle all of the required scenarios. This new executable is named proto-shim (proto-shim.exe on Windows) and is published alongside the proto binary.

This new executable solves all of the following problems (hopfully):

  • Locatable on PATH (is an .exe for Windows)
  • Can pipe/redirect data
  • Handles stdin prompts/interactivity
  • Supports ctrl+c interruptions
  • Passes parent signals to child processes
  • Attempts to kill child processes on parent exit
  • Bubbles exit codes
  • Native performance
  • Doesn't require special privileges (no symlinks)

How to test?

If you're interested in testing this new implementation (we'd appreciate it), you can do so by downloading the latest release candidate from GitHub:

Once downloaded, unpack the archive, and move the proto and proto-shim binaries to the ~/.proto/bin directory (or the location of your PROTO_INSTALL_DIR environment variable). From here, you can execute proto or your tool binaries as normal.


If you run into issues, try deleting the old ~/.proto/shims directory and trying again. If problems still persist, please report an issue or reach out to us on Discord!


On macOS, you may need to add the binary to the trusted list, in your Priacy & Security settings. This can also be achieved on the command line with xattr -c ~/.proto/bin/*.

What to test?

Basically everything. We want to ensure that all of the functionality in What's new? works as expected, so simply go about your day to day development and let us know if you run into any issues!