The Truth Behind “true”

Among the many useful commands you will find as standard on any POSIX system is “true”. This command does absolutely nothing, but returns a successful exit status. (There is also “false”, which also does nothing, but always returns a failure status. If anyone is curious as to how you would make use of these in shell scripts, just ask.) This page <http://trillian.mit.edu/~jc/humor/ATT_Copyright_true.html> gives the history of the “true” command from the original AT&T Unix--it was essentially a shell script that did absolutely nothing at all. Yet AT&T claimed copyright on it. This article <http://www.theregister.co.uk/2016/02/10/line_break_ep2/> includes, among its examples of supposedly bad code, the full source of the GNU “true” program (which actually also shares its source with the “false” program), which runs to 80 lines, as compared to the version from OpenBSD, which is just four lines (including a blank line and comments). But as pointed out in the previous link, the GNU version uses less memory and runs faster.

That last sentence threw me. Good read, thanks LDO! -- Securely sent with Tutanota. It's good, you should try it: https://tutanota.com 11. Feb 2016 14:13 by ldo(a)geek-central.gen.nz:
Among the many useful commands you will find as standard on any POSIX system is “true”. This command does absolutely nothing, but returns a successful exit status. (There is also “false”, which also does nothing, but always returns a failure status. If anyone is curious as to how you would make use of these in shell scripts, just ask.)
This page <> http://trillian.mit.edu/~jc/humor/ATT_Copyright_true.html> > gives the history of the “true” command from the original AT&T Unix--it was essentially a shell script that did absolutely nothing at all. Yet AT&T claimed copyright on it.
This article <> http://www.theregister.co.uk/2016/02/10/line_break_ep2> > includes, among its examples of supposedly bad code, the full source of the GNU “true” program (which actually also shares its source with the “false” program), which runs to 80 lines, as compared to the version from OpenBSD, which is just four lines (including a blank line and comments). But as pointed out in the previous link, the GNU version uses less memory and runs faster. _______________________________________________ wlug mailing list | > wlug(a)list.waikato.ac.nz Unsubscribe: > http://list.waikato.ac.nz/mailman/listinfo/wlug
participants (2)
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Eric Light
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Lawrence D'Oliveiro