What is -z if [-z "$ {FILE_LIST}"]

Question

In this case, -z in the shell script if [ -z "${FILE_LIST}" ] ?

Answer 1

[ matches test . And man test gives:

  -z STRING the length of STRING is zero 

Note. On some platforms [ is a symbolic link or hard link to test

Answer 2

From help test :

  -z STRING True if string is empty. 

Answer 3

-z for a string of zero length.

Answer 4

I think if you use bash then it will return true if the length of the string is zero (so in your case there are no files in the list).