sion of the form ${param:offset[:length} is used, an `offset' that evaluates to a number less than zer... if the expanded value of param is unset or null, and $param otherwise.
To use negative offsets tha... begin with a minus sign, separate the minus sign and the colon with a space.
<code>${string:position}... ion.
<code>
echo ${*:2} # Echoes second and following positional parameters.
echo ${@:2}
de>
[[ $a == z* ]] # True if $a starts with an "z" (pattern matching).
[[ $a == "z*" ]] # Tr... matching).
[ $a == z* ] # File globbing and word splitting take place.
[ "$a" == "z*" ] ... ed within a [ ] construct.
See Example 27-11 for an application of this comparison operator.
----
-z
... string be quoted within the test brackets. Using an unquoted string with ! -z, or even just the unquo
