zig:tldr:f416c
zig: Create and run a test build.
$ zig test ${filename-zig}
try on your machine
This command is using the zig command-line tool to run a test file.
The ${filename-zig} syntax is a shell parameter expansion. It takes the value of the filename variable and substitutes it into the command. If filename is not set, it will substitute with the value zig.
So essentially, the command will run a test file with the name stored in the filename variable (if it is set), or with the name zig if the filename variable is not set.
This explanation was created by an AI. In most cases those are correct. But please always be careful and
never run a command you are not sure if it is safe.