--, in gnu flags speak, says to the flag parser, anything after -- is not a flag, even if it starts with a -. It's still up the program what it wants to do with those arguments.

(~/src) % cat main.go
package main

import (
        "fmt"
        "os"
)

func main() {
        fmt.Println(os.Args)
}
(~/src) % go run -- main.go -- anything
[/var/folders/wh/k4ydm2jx2tb5tgfvdcddl3ym0000gn/T/go-build725222586/b001/exe/main -- anything]

In the case of the cat example you gave, cat expects each of the arguments provided it to be files, so the second -- is treated as a file named --. I don't see why go run should follow those semantics

--, in gnu flags speak, says to the flag parser, anything after -- is not a flag, even if it starts with a -. It's still up the program what it wants to do with those arguments.

(~/src) % cat main.go

package main



import (

        "fmt"

        "os"

)



func main() {

        fmt.Println(os.Args)

}

(~/src) % go run -- main.go -- anything

[/var/folders/wh/k4ydm2jx2tb5tgfvdcddl3ym0000gn/T/go-build725222586/b001/exe/main -- anything]

In the case of the cat example you gave, cat expects each of the arguments provided it to be files, so the second -- is treated as a file named --. I don't see why go run should follow those semantics

IIRC, it’s POSIX.

Maybe at least we should add documentation for that?

IIRC, it’s POSIX.

Yes, you are completely correct. I realised after I wrote this that -- probably isn't just a GNUism.

Maybe at least we should add documentation for that?

I don't understand what there is to document, the second -- isn't interpreted as a file because its passed to main.go as os.Args. If anything its the operation of the first -- that is confusing to me because of the history of the go tools not using GNU style flags.