NOTE: This is only valid if you already have successfully installed SFDX at least once in WSL, and want to update it.
It looks like I'm the only one that continues to regularly get this Error: HTTP 403: Invalid channel stable
everytime I run sfdx update
.
I don't want to reinstall every single time, so the compromise that seems to work is to download the zip again and untar it:
1. wget https://developer.salesforce.com/media/salesforce-cli/sfdx/channels/stable/sfdx-linux-x64.tar.xz , or
1. wget https://developer.salesforce.com/media/salesforce-cli/sfdx/channels/stable-rc/sfdx-linux-x64.tar.xz , if you want the RELEASE CANDIDATE
2. tar xJf sfdx-linux-x64.tar.xz -C ~/sfdx --strip-components 1 , this may take a while.
And that should do it. To confirm, run sfdx --version
If you want even more, and want to use the weekly updates, the releases can be seen here. Yes, there are quite a few versions ahead of the "stable" and "stable-rc" ones.