Hello,

I'm trying to figure out a way to use a Perl script to modify a log file that is being written to by a production web server. Specifically, I need a way to extract lines with the previous day's date from the log without shutting down the server or causing it to lose it's open file handle to the log file. Currently I use the following on the command line successfully:
grep 19/May access > access.030519;
grep -v 19/May access > temp.access; cat temp.access > access;
The data for the current day, 20/May, keeps getting written to the newly overwritten access file. I'm guessing this works because the cat temp.access>access occurs so quickly that it grabs the inode just released, which is the same inode the access file was using before the redirect overwrote it. Anyway, I would like to automate this process.
My question, is there a way to do this more safely in Perl? Should I just do the same thing in Perl using system()?

Thanks for any suggestions.