This assumes you are familiar with Bash Functions. If not, check out my article Getting Started with functions.

Returning values from a function is Bash is rough. Whenever possible, I would instead go with some other scripting language, such as Python or Perl. But, if you must use Bash, here is an example of how you can have a function that returns a value.

#!/bin/bash

function request {
  echo hello
}

response=$(request)

echo "response = $response"

In this example, "hello" should be returned, like this.

~]$ bash example.sh
response = hello

As a much more practical example, here is a function that should return the return code of a command.

#!/bin/bash

function ps_command_return_code {
  stdout=$(ps -ef | grep foo | grep -v " grep ")
  rc=$?
  echo $rc
}

return_code=$(ps_command_return_code)

echo "return_code = $return_code"

In this example, 0 or 1 should be returned.

~]$ bash example.sh
return_code = 1