Snippets

Поиск Коллекции О проекте

Логин

Feature Group

bash internal / data manipulations / string manipulation and expansions / parameter expansion / default value substitution (3)

Feature Group

bash internal / data manipulations / string manipulation and expansions / parameter expansion / default value substitution (3)

bash

This demonstrates providing a default value for a variable if it is unset or empty using parameter expansion in Bash.


echo "${foo:-"DefaultValueIfFooIsMissingOrEmpty"}"
# => DefaultValueIfFooIsMissingOrEmpty
# This works for null (foo=) and empty string (foo=""); zero (foo=0) returns 0.
# Note that it only returns default value and doesn't change variable value.

bash internal data manipulations string manipulation and expansions parameter expansion default value substitution

bash

This demonstrates providing a default value for a variable if it is unset or null.


${foo:-val}

bash internal data manipulations string manipulation and expansions parameter expansion default value substitution

bash

This demonstrates the use of a default value in Bash using parameter expansion.


echo ${foo:-'default'}

bash internal data manipulations string manipulation and expansions parameter expansion default value substitution

bash

This demonstrates providing a default value for a variable if it is unset or empty using parameter expansion in Bash.


echo "${foo:-"DefaultValueIfFooIsMissingOrEmpty"}"
# => DefaultValueIfFooIsMissingOrEmpty
# This works for null (foo=) and empty string (foo=""); zero (foo=0) returns 0.
# Note that it only returns default value and doesn't change variable value.

bash internal data manipulations string manipulation and expansions parameter expansion default value substitution

bash

This demonstrates providing a default value for a variable if it is unset or null.


${foo:-val}

bash internal data manipulations string manipulation and expansions parameter expansion default value substitution

bash

This demonstrates the use of a default value in Bash using parameter expansion.


echo ${foo:-'default'}

bash internal data manipulations string manipulation and expansions parameter expansion default value substitution