What's the appropriate Go shebang line?

Solution 1:

//usr/bin/go run $0 $@ ; exit

example:

//usr/bin/go run $0 $@ ; exit
package main

import "fmt"

func main() {
    fmt.Println("Hello World!")
}

go treat // as a single line comment and shell ignore extra /

Update: Go installation may be in a different location. The syntax below will take that into account, and works for Macs:

//$GOROOT/bin/go run $0 $@ ; exit

Solution 2:

I prefer this:

///usr/bin/true; exec /usr/bin/env go run "$0" "$@"

This has several advantages compared to the answer by هومن جاویدپور:

• The ///usr/bin/true accomplishes the feat of simultaneously being valid Go and shell syntax. In Go it is a comment. In shell, it is no-op command.

• Uses exec to replace the new shell process instead of launching a grandchild process. As a result, your Go program will be a direct child process. This is more efficient and it's also important for some advanced situations, such as debugging and monitoring.

• Proper quoting of arguments. Spaces and special characters won't cause problems.

• The leading /// is more standards compliant than just //. If you only use //, you run the risk of bumping into implementation-defined behaviour. Here's a quote from http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html:

If a pathname begins with two successive / characters, the first component following the leading / characters may be interpreted in an implementation-defined manner, although more than two leading / characters shall be treated as a single / character.

I have tested this answer with bash, dash, zsh, and ksh.

Example:

///usr/bin/true; exec /usr/bin/env go run "$0" "$@"
package main
import "fmt"
func main() {
    fmt.Println("你好！")
}

Solution 3:

There isn't one by default. There is a third-party tool called gorun that will allow you to do it, though. https://wiki.ubuntu.com/gorun

Unfortunately the compilers don't like the shebang line. You can't compile the same code you run with gorun.

Solution 4:

Go programs are compiled to binaries; I don't think there is an option to run them directly from source.

This is similar to other compiled languages such as C++ or Java. Some languages (such as Haskell) offer both a fully compiled mode and a "script" mode which you can run directly from source with a shebang line.