Aron Griffis <[EMAIL PROTECTED]> wrote: ... > Additionally, I noted that the Single UNIX Specification does not make > application recommendations for tail, although it refers to the older > syntax as obsolescent.
SUSv2 is pretty old. POSIX 1003.1-2001 is more relevant these days. Usage like `tail -1', `head +2', `sort +1' has been classified as obsolescent for many years. Recently, it has finally become officially `obsolete'. A little background: A long time ago, POSIX decided that certain types of options (like `-1' +6, etc.) should eventually be considered invalid. That's why people have been moving away from uses of e.g., `sort +N' to `sort -kM,M'. Less well known is the fact that commands like these head -1 tail +2 tail -4 uniq -3 (and more) are all technically obsolete, now. And if you build the GNU coreutils on a system that conforms to POSIX 1003.1-2001, then you'll find that the above all fail, e.g. like this: $ head -1 head: `-1' option is obsolete; use `-n 1' Try `head --help' for more information. [Exit 1] >From the coreutils documentation: For example, if you are running older software that assumes an older version of POSIX and uses `sort +1', `head -1', or `tail +1', you can work around the compatibility problems by setting `_POSIX2_VERSION=199209' in your environment. > The pain I'm seeing in the Gentoo Linux distribution, along with the > above research, leads me to question the rationale behind removing the > -number syntax in the GNU coreutils. Personally, I don't see a > motivation for their removal, since the older syntax is unambiguous and > in heavy use by thousands of UNIX scripts already in existence. It Short answer: it's required for conformance to POSIX 1003.1-2001. See the `Standards Conformance' section in the coreutils documentation. E.g., run `info coreutils standards'. Since you're encountering this problem, it's almost certainly the result of your building coreutils with a C library and headers that indicate the system conforms to POSIX 1003.1-2001 by virtue of the definition of _POSIX2_VERSION in <unistd.h>. > doesn't seem fruitful for the Gentoo developers (along with developers > of other distributions) to spend our time making this trivial change in > hundreds of packages, and trying to push the changes upstream. You may find solace in the fact that you're not alone :-) All distributions that care about standards conformance are (or will be) facing the same battle. Some began making such changes a few months ago, so you may have less work than you think. > Would the coreutils maintainers consider reinstating the older syntax to > save us the unnecessary toil? If that is not considered an option, > would you mind explaining the rationale behind making this change to the > head/tail programs? I checked the coreutils FAQ but didn't find > coverage of this topic. I suggest you do something like what Debian has done: Give yourselves a little breathing room by making it so coreutils' lib/posixver.c is compiled with _POSIX2_VERSION #defined to a value so that it doesn't cause all that trouble just yet. Then, try to convince gentoo/upstream developers to set _POSIX2_VERSION=200112 in their environment and to fix any problems that are exposed. _______________________________________________ Bug-coreutils mailing list [EMAIL PROTECTED] http://mail.gnu.org/mailman/listinfo/bug-coreutils
