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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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sttime(3)						    ShapeTools Toolkit Library							 sttime(3)

NAME
stMktime, stWriteTime - date and time handling SYNOPSIS
#include <config.h> #include <sttk.h.h> time_tstMktime (char *string); char*stWriteTime (time_t date); DESCRIPTION
stMktime scans the given string and tries to read a date and time from it. It understands various formats of date strings. The following is a list of all valid formats, optional parts in brackets. [Tue] Jan 5[,] [19]93 This includes the standard asctime(3) format. Jan 5 With no year given, the year defaults to the current year. [19]93/01/05 This notation requires month and day represented by exactly two digits. 5.1.[19]93 This is the usual German notation. 5.1. German notation referencing the current year. A certain time, given together with the date must always have the following form. hours:minutes[:seconds] Each of the fields must be an integer value within the proper range (hours: 0-23, minutes and seconds: 0-59). Values below 10 may be written as one digit numbers. The time value may be placed anywhere in the date string: at the beginning, at the end, or somewhere in the middle. Any amount of white- space may be given between a field of the time value and the separating colon. The time is always considered to be local time. stWriteTime generates a time string similar to asctime(3) from its date argument. SEE ALSO
asctime(3) BUGS
Time Zone Names within the time string (like `MET') are not handled properly. In most cases they will cause a failure. sttk-1.7 Thu Jun 24 17:43:35 1993 sttime(3)
All times are GMT -4. The time now is 07:11 AM.
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