Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/17/84; site opus.UUCP Path: utzoo!watmath!clyde!burl!ulysses!allegra!bellcore!decvax!genrad!wjh12!talcott!harvard!seismo!hao!cires!nbires!opus!rcd From: rcd@opus.UUCP Newsgroups: net.unix Subject: Re: Unix cmd names obscure? Message-ID: <981@opus.UUCP> Date: Tue, 18-Dec-84 20:09:15 EST Article-I.D.: opus.981 Posted: Tue Dec 18 20:09:15 1984 Date-Received: Sat, 22-Dec-84 01:19:56 EST References: <229@pyuxt.UUCP> Organization: NBI,Inc, Boulder CO Lines: 33 > "... once the tape is done, you can run a standard IBM utility > like IEBGENER to print it on a high speed printer." > > And they say Unix command names are obscure... Not half, they aren't! If you think the description above is cryptic, realize that it's only a glimpse into a bizarre universe... IEBGENER is the utility you use to copy things. Don't be confused by the fact that there is an IEBCOPY, which does something else entirely. And to delete files, you use IEFBR14. This wonderfully mnemonic name is derived from a magic IBM prefix (IEF) and a branch instruction (Branch Register 14) which is effectively a do-nothing program, since register 14 is the standard place for the "return address" of a main program. Huh? Delete a file...oh yeah, we were talking about that...well, you delete files as a side-effect of running a program, so IEFBR14 gives you a harmless program which can be run for its side effect. [Interesting side-side issue: You may have heard the quip that "Every program has at least one bug and can be shortened by at least one instruction"--from which, by induction, one can deduce that every program can be reduced to one instruction which doesn't work. IEFBR14, if written as the obvious, single-instruction program " BR 14", does NOT work. Reason: It fails to set a proper value for its return code, which means that it may fail mysteriously. An entertaining rumor has it that this bug actually existed in IEFBR14 once. But don't get too cocky--the same bug also exists in the UNIX world, since many C programs terminate by falling out the bottom of the main program and most C startup routines simply take whatever garbage return value this produces as the exit status of the program.] -- Dick Dunn {hao,ucbvax,allegra}!nbires!rcd (303)444-5710 x3086 ...Are you making this up as you go along?