Invalid first argument to `exec.Command`

`os/exec` runs programs directly (using variants of the
[fork](https://en.wikipedia.org/wiki/Fork_(system_call)) and
[exec](https://en.wikipedia.org/wiki/Exec_(system_call)) system calls
on Unix systems). This shouldn't be confused with running a command in
a shell. The shell will allow for features such as input redirection,
pipes, and general scripting. The
shell is also responsible for splitting the user's input into a
program name and its arguments. For example, the equivalent to `ls /
/tmp` would be `exec.Command("ls", "/", "/tmp")`.

If you want to run a command in a shell, consider using something like
the following – but be aware that not all systems, particularly
Windows, will have a `/bin/sh` program:

```
exec.Command("/bin/sh", "-c", "ls | grep Awesome")
```
