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Top Forums Shell Programming and Scripting Help with perl code understanding Post 302859309 by Smiling Dragon on Wednesday 2nd of October 2013 06:27:35 PM
Old 10-02-2013
This code is watching STDIN for a particular string pattern - "A word","one or more spaces","a number""one or more spaces","3 numbers separated by colons"

This is of a form that looks like it could be a date and time:
eg March 16 12:00:00

It sets $now to be the current time and $old to be 30 minutes ago.
It then figures out a unix timestamp from the supplied date string, and if that date is newer that 30 mins ago and older then now (ie if it's in the last 30 mins) it prints the date to the screen. Otherwise it does nothing.

I'd imagine that if you piped a file into this, it would output only the lines that have a datestamp in them in the last 30 minutes.

Note that if your system clock is in a different timezone to that of the file you are piping in, it won't work correctly.
 

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Time::Duration::Parse(3pm)				User Contributed Perl Documentation				Time::Duration::Parse(3pm)

NAME
Time::Duration::Parse - Parse string that represents time duration SYNOPSIS
use Time::Duration::Parse; my $seconds = parse_duration("2 minutes and 3 seconds"); # 123 DESCRIPTION
Time::Duration::Parse is a module to parse human readable duration strings like 2 minutes and 3 seconds to seconds. It does the opposite of duration_exact function in Time::Duration and is roundtrip safe. So, the following is always true. use Time::Duration::Parse; use Time::Duration; my $seconds = int rand 100000; is( parse_duration(duration_exact($seconds)), $seconds ); FUNCTIONS
parse_duration $seconds = parse_duration($string); Parses duration string and returns seconds. When it encounters an error in a given string, it dies an exception saying "Unknown timespec: blah blah blah". This function is exported by default. AUTHOR
Tatsuhiko Miyagawa <miyagawa@bulknews.net> COPYRIGHT
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself. Some internal code is taken from Cache and Cache::Cache modules on CPAN. SEE ALSO
Date::Manip, DateTime::Format::Duration, <http://use.perl.org/~miyagawa/journal/30310> perl v5.10.0 2008-06-02 Time::Duration::Parse(3pm)
All times are GMT -4. The time now is 09:57 AM.
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