Return Status - Bash Execution Replay

Bash functions return status codes, not rich values. That makes functions useful inside if statements.

Program

Play the script to see is_even return success and choose the then branch.

return_status.sh

#!/usr/bin/env bash

is_even() {
  local value="$1"
  (( value % 2 == 0 ))
}

number=8
if is_even "$number"; then
  echo "even"
else
  echo "odd"
fi

return status A function's status is the status of its last command unless it calls `return`.

predicate A predicate command answers a yes/no question through its exit status.