SET system time

[CJason]

Anyone have a good way to set the system time...preferably, platform independently? In specific, I need to take the current date, and adjust the time + or - an hour.

Thanks in advance!

 

[Kirsle]

Do you need to actually modify the system time, so that when your script quits running the clock on the system will show a different time + or - an hour?

If you only need an hour difference in time for your script, just add or subtract from the value you get from time().

my $now = time();
print "right now: " . localtime($now) . "\n";

my $future = $now + 60*60; # add an hour
print "an hour from now: " . localtime($future) . "\n";

my $past = $now - 60*60; # minus an hour
print "an hour ago: " . localtime($past) . "\n";

Most other time functions besides localtime use a value like what time() returns, so you can just modify the return value of time() in most cases. 60*60's logic is "60 seconds = 1 minute * 60 = 1 hour".

Cuvou.com | My personal homepage

perl -e '$|=$i=1;print" oo\n<|>\n_|_";x:sleep$|;print"\b",$i++%2?"/":"_";goto x;'

 

[CJason]

Actually, I'm looking to change the actual system time...so that the system clock has changed after the script runs.

 

[Kirsle]

You probably won't be able to do this in a system-independent way.

In Linux it involves copying a file from /usr/share/zoneinfo where /etc/localtime is (a lot of tutorials say to symlink /etc/localtime to a file there, but I've run into problems with that in the past, for instance if you have /etc/localtime as a symlink and then try to copy (not symlink) another time zone file to it, it will actually *overwrite* the time zone it used to be linked to, instead of breaking the link).

Example, set to Pacific time,

cp /usr/share/zoneinfo/America/Los_Angeles /etc/localtime
OR
cp /usr/share/zoneinfo/PST8PDT /etc/localtime

On Windows it would likely involve using the Win32 API to change the time, but I don't have any details on how this is done.

Cuvou.com | My personal homepage

perl -e '$|=$i=1;print" oo\n<|>\n_|_";x:sleep$|;print"\b",$i++%2?"/":"_";goto x;'

 

[Annihilannic]

I think the OP meant to change the time, not the time zone... i.e. using the date MMDDHHMM command for example.

Annihilannic.