Executing a "batch script" (.bat) in Windows

[Philipp Schumann]

So, my %PATH% has a directory containing the sass.bat script:

----

1. Using this..

os/exec.Command("sass.bat")

..returns an error --- exec: "sass.bat": executable file not found in %PATH%

Same with just "sass" instead of sass.bat. (Running both sass and sass.bat directly from the command-line works fine.)


2. Now, I try this alternative..

os/exec.Command("cmd", "/C", "sass.bat")

..returns an error --- exit status 1

Again, same with just "sass" instead of sass.bat. (Again, running both "cmd /C sass" and "cmd /C sass.bat" from the command-line works fine.)

----

So, calling all Windows gophers out there: how can I exec a batch file where its full file path isn't known but is known to be in %PATH% (which is usually enough for cmd /C)?

[Philipp Schumann]

Pre-emptive:

1. of course, it isn't the exec.Command() func that returns the error, but Run() or CombinedOutput()

2. regardless of "exit code 1", I can tell the sass.bat isn't properly called as it doesn't create a file it is expected to create. When I call it identically but manually from the command-line via cmd /C sass -args, it does create said output file, however.

[peterGo]

Philipp,

Put sass.bat in one of the directories that appears in the PATH output
from the set path command. Also, check that .BAT appears in PATHEXT.

sass.bat:

dir

sass.go

package main

import (
"fmt"
"os/exec"
)

func main() {
out, err := exec.Command("sass.bat").CombinedOutput()
if err != nil {
fmt.Println(err)
}
fmt.Println(string(out))
}

Peter

On Jun 9, 7:18 pm, Philipp Schumann <philipp.schum...@gmail.com>
wrote:

[brainman]

Show us your program and batch file.

Go uses CreateProcess https://code.google.com/p/go/source/browse/src/pkg/syscall/exec_windows.go#330 to execute programs. The way it is used http://msdn.microsoft.com/en-us/library/windows/desktop/ms682425(v=vs.85).aspx , this comment is applied:

...

To run a batch file, you must start the command interpreter; set lpApplicationName to cmd.exe and set lpCommandLine to the following arguments: /c plus the name of the batch file.

...

If you need to find batch file in the PATH, perhaps http://golang.org/pkg/os/exec/#LookPath will help.

Alex

[Philipp Schumann]

Hi Peter, thanks! Now this is VERY interesting:

1. if I run the program directly from the command-line, it works fine (path and pathext have both been correct from the beginning regarding sass.bat)

2. but the actual use-case is that this program is ITSELF being os/exec.Run() from yet another Go program! And this doesn't work and yields:

exec: "sass.bat": executable file not found in %PATH%

What a mystery!

[Philipp Schumann]

Issue resolved. The path was recently added and the "outer process" invoking my Go processes -- Sublime Text 2 -- sadly never seems to refresh its PATH information. (More specifically, seems like no running Windows processes' ENV variables are ever refreshed by Windows?!?!) Restarting ST2 made my stuff work.

[Ibrahim M. Ghazal]

On Mon, Jun 10, 2013 at 1:22 PM, Philipp Schumann
<philipp....@gmail.com> wrote:
> Issue resolved. The path was recently added and the "outer process" invoking
> my Go processes -- Sublime Text 2 -- sadly never seems to refresh its PATH
> information. (More specifically, seems like no running Windows processes'
> ENV variables are ever refreshed by Windows?!?!) Restarting ST2 made my
> stuff work.
>

I've never heard of any operating system that "refreshes" environment
variables of running processes. You can change them *before* running
the process, but once it's running, you can't modify them from outside
the process.

[chris dollin]

On 10 June 2013 12:24, Ibrahim M. Ghazal <img...@gmail.com> wrote:

I've never heard of any operating system that "refreshes" environment
variables of running processes. You can change them *before* running
the process, but once it's running, you can't modify them from outside
the process.

I seem to recall that Risc OS's system variables, which are/were its equivalent

of environment variables, were system-global.

Chris

--
Chris "allusive" Dollin