Open file and Splitting String in Perl
What I gonna do is to read a bunch of data from a file, and perform some data processing from the string.
- split() is the Perl function which I will use for filtering the data.
- open for reading a file into array.
I took MRTG’s data log to do some data processing. On the first column of MRTG log file is Unix timestamp, I would like to print the unix Timestamp to human readable date and time, the other columns are traffic in and out in bytes, which I want to find out which traffic is more than certain values.
Below is the sample of MRTG’s log file (mrtg.log), it’s more than 1000 lines
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1263954197 4778984843734474 1971197295597596 1263954197 184057628 54266478 184057628 54266478 1263953906 181938506 53715962 181938506 53715962 1263953700 182506581 53937120 182750043 54031903 |
Perl script will read the log data, split the data by space on each line into array, perform condition compare and find out the date.
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#!/opt/local/bin/perl open FILE, "mrtg.log"; my @logs = \<FILE\>; foreach my $log (@logs) { my @data = split(' ', $log); if ($data[1] > 500000000) { print scalar localtime($data[0]), " ## ", $data[1], " ## ", $data[0], "\n"; } } |
After going through more than 1000 lines of MRTG log, below is the output
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Wed Jan 20 10:23:17 2010 ## 4778984843734474 ## 1263954197 Fri Jan 30 08:00:00 2009 ## 847491342 ## 1233273600 Tue Jan 13 08:00:00 2009 ## 844059530 ## 1231804800 |
This shows there were traffic spike twice during some where in Jan 2009. That’s split() and open in Perl.