Question

Is it possible to set variable defaults for a shell script using short circuiting?

Script call 1: my_script.sh "apple" "carrot"

Script call 2: my_script.sh "apple"

my_script.sh:

#!/bin/bash
fruit=$1
vegetable=$2 || "green bean"

# Do something with fruits and vegetables 

When I do that, it doesn’t seem like the default ever gets used.

Answer 1

Did you indicate that the script should use a specific shell? I always defaul to use bash as so:

#!/bin/bash

Nice explanation of the concept here.

EDIT: Okay, I better understand the question now. The original poster wants to set default values if variables are not passed. Nice explanation on setting default variables here. Try this script:

#!/bin/bash

fruit=${1-apple}
vegetable=${2-green bean}

echo $fruit;
echo $vegetable;