Like most scientific organizations, we specify time in UTC. Recently, a program that is run from the cron started using the wrong time. I discovered that the 'date' command was now outputting EST instead of UTC. I then discovered that the current version of /etc/localtime on this machine was installed the day that the behavior of 'date' changed and that /etc/localtime is now a link to /usr/share/zoneinfo/US/Eastern. Now for the confusing part: 'date' still outputs UTC when not run in a cron job. Whether I type in 'date' or put 'date' in a C shell script, I get UTC. But if I run that same C shell script as a cron job, it switches to EST. I can accept that the new /etc/localtime changed the behavior of 'date', but I don't understand why the change only occurs in cron jobs. Can anyone explain this?

(the environment variable TZ on this machine is set to UTC0.)

Probably because for your logged in user you are setting TZ to UTC0 in one of the profiles (.bashrc, /etc/profile ....) but the cron job is getting a minimal environment that doesn't set TZ at all so it is using the /etc/localtime.

Have a look at:
http://www.linuxquestions.org/questi...-script-36931/

You can set the TZ explicitly in your cron job OR revert your /etc/localtime to use the one for UTC.

1 members found this post helpful.