e>
----
-n
string is not null.
Caution
The -n test requires that the string be quoted within the test brackets. Using an unquoted string with ! -z, or ... r a string is null ===
<code>
#!/bin/bash
# str-test.sh: Testing null strings and unquoted strings,
#+ but not ... ]]</code>
The -o and -a operators work with the test command or occur within single test brackets.
<code>
if [ "$expr1" -a "$expr2" ]
the
