-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.

Links

• Bash manual
• POSIX specification of test

Examples

Different ways to test if a string is empty:

1 2 3 4

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