expand to word if the expanded value of param is unset or null, and $param otherwise.
To use negati... s less efficient than ${variable##/*} because it runs in its own separate process rather than within th... ameter:-word}
Provide a default if parameter is unset or null.
Example:
echo ${1:-"default"}
Note:... Assign a value to parameter if it was previously unset or null.
Example:
echo ${HOME:="/home/.nohom
