Check out the SHAMELESS Ole Tange and his bizarre attempts to simultaneously force people to obey academic citations while at the same offering you the chance to throw the academic process in the bin for a mere 10000 EUR payment to him.
I wish I was joking. GNU Nagware! It literally nags you with a warning message every time you use it until you tell it you agree to cite him or pay him 10000 EUR.
I have no idea how the Gnu foundation allows this!
Take a look at http://git.savannah.gnu.org/cgit/parallel.git/tree/src/paral...
sub bibtex { # Returns: N/A print join("\n", "Academic tradition requires you to cite works you base your article on.", "When using programs that use GNU Parallel to process data for publication", "please cite:", "", "\@article{Tange2011a,", " title = {GNU Parallel - The Command-Line Power Tool},", " author = {O. Tange},", " address = {Frederiksberg, Denmark},", " journal = {;login: The USENIX Magazine},", " month = {Feb},", " number = {1},", " volume = {36},", " url = {http://www.gnu.org/s/parallel},", " year = {2011},", " pages = {42-47}", " doi = {10.5281/zenodo.16303}", "}", "", "(Feel free to use \\nocite{Tange2011a})", "", "This helps funding further development; and it won't cost you a cent.", "If you pay 10000 EUR you should feel free to use GNU Parallel without citing.", "", "If you send a copy of your published article to tange\@gnu.org, it will be", "mentioned in the release notes of next version of GNU Parallel.\n\n", ); while(not -e $ENV{'HOME'}."/.parallel/will-cite") { print "\nType: 'will cite' and press enter.\n> "; my $input = <STDIN>; if($input =~ /will cite/i) { mkdir $ENV{'HOME'}."/.parallel"; if(open (my $fh, ">", $ENV{'HOME'}."/.parallel/will-cite")) { close $fh; print "\nThank you for your support. It is much appreciated. The citation\n", "notice is now silenced. You may also use '--will-cite'.\n", "If you use '--will-cite' in scripts you are expected to pay\n", "the 10000 EUR, because you are making it harder to see the\n", "citation notice.\n\n";