execution is terminated.
The return value of the test functions is used as result of the test: true, the test succeeded; false, the test failed. Remembering that the return value of a fu... . Using a function cuts this duplication down. To test for characters only, we can use awk. Here's the function to test if we only get upper or lower case characters.
... OK. A return code is then executed based on this test. Using the return code enables the script to look cleaner when the test is done on the function on the calling part of the script.
To test the outcome of the function we can use this forma
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 ... ]]</code>
The -o and -a operators work with the test command or occur within single test brackets.
<code>
if [ "$expr1" -a "$expr2" ]
the
