backticks do not return any value in perl

Question

I wrote a perl script in Cygwin environment. Inside, I use backticks to execute another program, and returned value is assigned to a variable. It worked fine before I upgraded some packages in cygwin two weeks ago. Now the backticks do not return any value. Any thoughts?

Answer 1

Try checking the value of $?. It contains the return code of the last external command executed, but it's overloaded to contain extra information, such as the signal that killed the command and whether there was a core dump, etc.

The actual return code can be obtained through

my $return_code = $? >> 8;

If it's zero, the command executed successfully, if not, that's the error status the commadn exited with (what int main() returns with in C, for example).