in reply to
How to install CGI in ubuntu machine?
Apache has the error_log file which has specific details of failures. See Ovid's CGI Course from Tutorials->Web Programming, along with the Apache documentation.
By rote learning.
Via Genetic memory.
It's provided by my firmware.
I just remember them.
Thirty days hath September
My computer gets it right, usually.
I just ask someone else.
Someone punches me on the first of the month.
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