Revision 6 as of 2011-03-13 15:01:35

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What is it?

gorun is a tool enabling one to put a "bang line" in the source code of a Go program to run it, or to run such a source code file explicitly. It was created in an attempt to make experimenting with Go more appealing to people used to Python and similar languages which operate most visibly with source code.


As an example, copy the following content to a file named "hello.go" (or "hello", if you prefer):


package main

func main() {
    println("Hello world!")

Then, simply run it:

$ chmod +x hello.go
$ ./hello.go
Hello world!


gorun will:

  • write files under the home directory, so that the actual script location isn't touched (may be read-only)
  • avoid races between parallel executions of the same file
  • automatically clean up old compiled files that remain unused for some time (without races)
  • replace the process rather than using a child
  • pass arguments to the compiled application properly
  • handle GOROOT, GOROOT_FINAL and the location of the toolchain properly

Is it slow?

No, it's not, thanks to the Go (gc) compiler suite, which compiles code surprisingly fast.

Here is a trivial/non-scientific comparison with Python:

$ time ./gorun hello.go
Hello world!
./gorun hello.go  0.03s user 0.00s system 74% cpu 0.040 total

$ time ./gorun hello.go
Hello world!
./gorun hello.go  0.00s user 0.00s system 0% cpu 0.003 total

$ time python -c 'print "Hello world!"'                                                        
Hello world!
python -c 'print "Hello world!"'  0.01s user 0.00s system 63% cpu 0.016 total

$ time python -c 'print "Hello world!"'
Hello world!
python -c 'print "Hello world!"'  0.00s user 0.01s system 64% cpu 0.016 total

Note how the second run is significantly faster than the first one. This happens because a cached version of the file is used after the first compilation.

gorun will correctly recompile the file whenever necessary.

Where are the compiled files kept?

They are kept under the ~/.gorun directory.

You can remove these files, but there's no reason to do this. These compiled files will be garbage collected by gorun itself when they stop being used. This is done in a fast and safe way so that concurrently executing scripts will not fail to execute.

Ubuntu packages

There are Ubuntu packages available that include gorun:

sudo add-apt-repository ppa:niemeyer/ppa 
sudo apt-get update 
sudo apt-get install golang 

How to build and install gorun from source

First, obtain the code from Launchpad:

$ bzr branch lp:gorun

Then, build it:

$ cd gorun
$ make

Reporting bugs

Please report bugs at:


gorun is licensed under the GPL.


To get in touch, send a message to gustavo.niemeyer@canonical.com