-z STRING (conditional operator)

true if the string is empty, i.e. if its length is zero. This is usually only useful for strings, which contain variables or sub-expressions.

-n tests if a string is not empty.

Examples

Different ways to test if a string is empty:

test -z "$name" && echo "empty"
[ -z "$name" ] && echo "empty"
# Bash
[[ -z "$name" ]] && echo "empty"

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