Complex command in exec.Command() - bash

Question

I want to exec this command:
docker exec -it demoContainer bash -c "pip freeze" > "requirements.txt"
But don't find any example of this kind of complex commands with pipes, and output writes.
I tryed this:
cmd := exec.Command("docker", "exec -it demoContainer bash -c \"pip freeze\" > \"requirements.txt\"")
_, err = cmd.CombinedOutput()
And:
cmd := exec.Command("docker", "exec", "-it", "demoContainer", "bash", "-c", "pip freeze", ">", "scheduleDeploy/requirements.txt")
_, err = cmd.CombinedOutput()
But always crash with the following output:
Error: Exit status 1
Edit
Updates with answers ideas:
err = exec.Command("sh", "-c","'docker exec -it demoContainer bash -c 'pip freeze' > 'requirements.txt''").Run()
Output:
Exit error status 2

Answer 1

You don't have to use the shell for redirection, you can just let Go do it:
package main
import (
"os"
"os/exec"
)
func main() {
f, e := os.Create("requirements.txt")
if e != nil {
panic(e)
}
defer f.Close()
c := exec.Command(
"docker", "exec", "-it", "demoContainer", "bash", "-c", "pip freeze",
)
c.Stdout = f
c.Run()
}

Answer 2

The > redirection is a "shell" thing, not an "exec" thing. You will need to do one of "run bash, with the command you want executed" or "open a file, set the resulting os.File as the Stdout of the exec.Command, before starting it".
Either would probably solve the issue you are facing.
To use the "bash -c" version, something like:
exec.Command("bash", "-c", `docker exec -it demoContainer bash -c "pip freeze" > requirements.txt`)