Using variables in exec.Command Golang

Question

I am trying to use variables within the string

i have tried the following to no avail :(

astatus, _ := exec.Command("/bin/sh", "-c", "fs_cli -x\"callcenter_config agent get status\"", agent_uuid).Output()

astatus, _ := exec.Command("/bin/sh", "-c", "fs_cli -x\"callcenter_config agent get status\"" + agent_uuid).Output()

it does not seem to be parsing the output of the variable agent_uuid

any help would be much appreciated

Is `agent_uuid` supposed to be a new argument to `fs_cli` or a continuation of `get status`? Because if it's the latter you should use `+`. — Arkadiusz Drabczyk, Jan 23 '22 at 13:02
You have to run built executable under some debugger such as `strace` and see how the executable you want to run is run. — Arkadiusz Drabczyk, Jan 23 '22 at 13:15
change `Output()` to `.CombinedOutput()` and see what error it returns. — serge-v, Jan 23 '22 at 14:07

score 0 · Answer 1 · answered Jan 23 '22 at 16:37

You didn't provide an example of a correct command line invocation, and I'm not familiar with fs_cli. But I think your issues here is a quesiton of whitespace for the shell command.

astatus, _ := exec.Command("/bin/sh", "-c", "fs_cli -x\"callcenter_config agent get status\"", agent_uuid).Output()

That's going to produce a shell invocation such as:

/bin/sh -c" "fs_cli -x\"callcenter_config agent get status\"" agent_uuid

Because that's how you did the spaces. but looking at the fs_cli data online, it should probably be something more like:

"/bin/sh", "-c", "fs_cli -x \"callcenter_config agent get status agent_uuid\""

Actually there's really no purpose in using a shell command. You aren't using any bash features - it's just a passthrough to executing another program. So instead of formatting for shell, just invoke the program directly. Then, each argument will be a separate string, and you won't have to worry about whitespace:

astatus, err := exec.Command(
   "fs_cli",
   "-x",
   fmt.Sprintf("callcenter_config agent get status %s", agent_uuid),
).Output()

If you can't get this working, please make sure to edit the question with the exact invocation of fs_cli that you use at command line, with the whitespace in the correct place. Then it will be an easy matter to fix the invocation here.

astatus, _ := exec.Command(...)

Don't ever ignore errors in Go. Remember it doesn't raise exceptions - checking error status is generally the only way to detect runtime errors. You're hurting your own debugging by ignoring the error that might come from the command invocation.

Using variables in exec.Command Golang

1 Answers1