Roland Mainz wrote: > Chris Gerhard wrote: >> Roland Mainz wrote: >>> Darren J Moffat wrote: > [snip] >>> 2. I have great concerns about the abuse of the global environment >>> variable namespace - sooner or later this will backfire _badly_ if cron >>> and other applications have slightly different ways to interpret the >>> values. >> It would if they did. However since cron is interpreting all the >> variables in the way you expect I fail to see how this is an issue. TZ >> is treated as the timezone. If we went with .cron.tz cron would still >> have to set TZ to match this otherwise you would have a cron job wiht >> .cron.tz set to PST but running on a system in UTC would have the job >> seeing time as UTC while scheduled in PST. > > Two issues: > 1. You basically assign a double-functionality to the variables - they > affect both cron internal behaviour and they are exported into the > environment of the launched cron job. > For example: What do you want to do if you use the timezone "a" for the > cron entries but run the cron job with the default system timezone ?
With a crontab entry like this: TZ=UTC * * * 7 * env TZ=PST ..... > > 2. The scheme as described in the current ARC materials is not > extensible since you can't gurantee that you won't create namespace > clashes between variables which set/define cron-internal behaviour and > stuff which is exported into the environment (imagine you add a variable > called "VERSION" to define which version of the cron spec should be used > to interpret the cron entries - this would render the OS/Net build > defunct since environment variables override Makefile variables and > usr/src/Makefile.master contains a variable "VERSION" ... or short: > *BOOOOOM* ...). > Maybe you could say you only export a defined subset of these variables > (e.g. "SHELL", "HOME", "TZ") but that would make these other variables > more or less "local variables" and by the usual Unix shell conventions > such variable names should be at least spelled using lowercase > characters... I do. The only variables I export are SHELL, HOME and TZ since they are the only ones that effect cron. It does not allow the setting of any other variables. --chirs
