>Some people are really angry about GNU Parallel's citation "nag

the way I understand this, is that by requiring to interactively enter "will cite" the ability to run it as part of a larger script is broken. This would break a cron-job as well. The non-interactive nag in output would not cause such probles.

The non-interactive message in output of course could create problems on its own - especially if the nag would or would not display randomly. If someone intends to parse the output, this would require additional code to discard the nag. If the nag would sometimes display and sometimes not, this could randomly break stuff - if there was no nag during tests someone could not notice that they need to discard it.

But there are non-intrusive ways to insert some offensive message - they could be put to syslog, or a file with an offensive name/content would be created. My general idea is not to nag the users per se but do something that does not cause actual inconvenience for the user but is unacceptable in corporate environment.

For a GUI app a simple message box appearing once a month would not cause a major problem or hurt productivity of the end-user but I assume that for example Apple or Google would not find it acceptable for their software to display "f-off" even if this was rare.

For non-interactive/non-GUI software other ways to inject that message would be needed. For instance, a http server could inject additional X-F-Off header or a daemon could require env variable ICONSUMEFECES set to "daily"

> This would break a cron-job as well.

How so? GNU Parallel only outputs the notice if stderr is a terminal. I think you did not try this. Am I right about that?

It is litteraly the 3rd point in https://git.savannah.gnu.org/cgit/parallel.git/tree/doc/cita...

Did you try any of the other situations? Or are you simply speculating that this might cause problems without actually testing?

They’re probably angry because the nag may fall under GPL’s “no additional restrictions”.