syntax – Ternary operator (?:) in Bash

syntax – Ternary operator (?:) in Bash

ternary operator ? : is just short form of if/else

case $b in
 5) a=$c ;;
 *) a=$d ;;
esac

Or

 [[ $b = 5 ]] && a=$c || a=$d

Code:

a=$([ $b == 5 ] && echo $c || echo $d)

syntax – Ternary operator (?:) in Bash

If the condition is merely checking if a variable is set, theres even a shorter form:

a=${VAR:-20}

will assign to a the value of VAR if VAR is set, otherwise it will assign it the default value 20 — this can also be a result of an expression.

This approach is technically called Parameter Expansion.