06-09-2008
Problem number 1 is you're mixing date math with integer math. You cannot add 1 to your "0530" and expect to get the next day. For example, there is no integer "0530". There is an integer "530", however, and if you add 1 to it you will get "531". ...NOT the "0531" that you need. And, as you mentioned, adding 1 to that will not get you into June.
The problem of shell date arithmetic is fairly difficult. See
"Date math in Linux shell script?": Tech Support from Ask Dave Taylor! .
When you do your comparison, you can test for your end condition in either of two ways:
- If the current date == the end date (string comparison)
- If the current iterations number of seconds since the epoch is less than or equal to the end date's number of seconds since the epoch.
Also, here's a couple of more gotchas you need to be aware of. If you do your date math using "number of seconds since the Epoch",
- You may want your first date to actually be midnight of the first date- that is, the 0'th second of that day.
- You may want your second date to actually be 23:59:59 on that day.
This is because if you do your "begin <= end" comparison, you may be comparing 3pm on the end day to 2pm on the end day and that iteration of the script will not run.
I mention that because it's convenient to actually do the date math by:
- Convert the first date to the number of seconds since the epoch
- Increment the date by adding 86,400 (the number of seconds in a day) to the date for each iteration.
You also must be aware of when the year changes. Don't forget you may be comparing dates in January to dates in December.
-mschwage
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LEARN ABOUT DEBIAN
tv_sort
TV_SORT(1p) User Contributed Perl Documentation TV_SORT(1p)
NAME
tv_sort - Sort XMLTV listings files by date, and add stop times.
SYNOPSIS
tv_sort [--help] [--by-channel] [--output FILE] [FILE...]
DESCRIPTION
Read XMLTV data and write out the same data sorted in date order. Where stop times of programmes are missing, guess them from the start
time of the next programme on the same channel. For the last programme of a channel, no stop time can be added.
Tv_sort also performs some sanity checks such as making sure no two programmes on the same channel overlap.
--output FILE write to FILE rather than standard output
--by-channel sort first by channel id, then by date within each
channel.
--duplicate-error If the input contains the same programme more than once,
consider this as an error. Default is to silently
ignore duplicate entries.
The time sorting is by start time, then by stop time. Without --by-channel, if start times and stop times are equal then two programmes
are sorted by internal channel id. With --by-channel, channel id is compared first and then times.
You can think of tv_sort as converting XMLTV data into a canonical form, useful for diffing two files.
EXAMPLES
At a typical Unix shell or Windows command prompt:
tv_sort <in.xml >out.xml
tv_sort in.xml --output out.xml
These are different ways of saying the same thing.
AUTHOR
Ed Avis, ed@membled.com
perl v5.14.2 2006-03-02 TV_SORT(1p)