input command

Ernst Reissner <[email protected]> Fri, 7 Apr 2023 15:43:11 +0200
Newsgroups gmane.comp.tex.metapost
Message-ID <[email protected]>
Hello all,

I read the metapost manual by J.D. Hobby.

What I wonder: the 'command' input is used several times but it is 
introduced nowhere.

What is it? a macro?, a command??


Best Regards,

Ernst

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