What does the -z flag mean in the code below:if [ -z $TEST_PARAM ]; thenAnd is there a list of such flags?For a flag like ls -l, I know where to find it, but for a single flag, I didn't get any website describes it.
what does the -z flag mean here
shell script;test
-z STRING means:the length of STRING is zeroYou can see a list of all of these with man test.[ is an alias for the test command,  although usually implemented by your shell in practice. You probably have a /bin/[, though. All of these -X tests are options to test.