if [[ -a $PS_HOME/scripts/$FILE.ctl ]]
in the above statement, what is the meaning -a
it means if file exists then condition will be true.
-a file
True, if file exists.
$PS_HOME/scripts/$FILE.ctl -> here PS_HOME and FILE are variables and will be replaced with values in it.
so the conditon checks if .ctl file exist at the path then proceed.