I'm looking at the following code:
if [ -z $2 ]; then echo "usage: ...(The 3 dots are irrelevant usage details.)
Maybe I'm googling it wrong, but I couldn't find an explanation for the -z option.
4 Answers
-z string True if the string is null (an empty string)
-z
string is null, that is, has zero length
String='' # Zero-length ("null") string variable.
if [ -z "$String" ]
then echo "\$String is null."
else echo "\$String is NOT null."
fi # $String is null.test -z returns true if the parameter is empty (see man sh or man test).
The expression -z string is true if the length of string is zero.
