Hi! ----
[The following is either a PSARC or OS/Net gatekeeper question - I don't know it exactly and therefore both end-up in the CC: field] During PIT (=PreIntegration Testing) for ksh93-integration update2 (which includes an opensource replacement for /usr/bin/tail and /usr/xpg4/bin/tail (note that both are built from the same source) - see http://arc.opensolaris.org/caselog/PSARC/2009/249/20090420_roland.mainz.2) we hit a bug with "tail -r/+r" and during fixing it we've hit the following issue: SXCE B110 tail(1) manual page defines "tail"'s "-r" option like this: -- snip -- -r Reverse. Copies lines from the specified starting point in the file in reverse order. The default for r is to print the entire file in reverse order. -- snip -- PSARC/2009/249 defines it the same way but with a shorter description: -- snip -- -r, --reverse Output lines in reverse order. -- snip -- Both AFAIK are thought that option "-r" works like "tail -<number> | rev -l" ("rev -l" outputs the incoming lines in reverse order). The /usr/bin/tail+/usr/xpg4/bin/tail commands in SXCE B110 does this correctly when I use something like "-<number>r", for example: -- snip -- $ print "1\n2\n3\n4\n5\n6" | /usr/xpg4/bin/tail -4r 6 5 4 3 $ print "1\n2\n3\n4\n5\n6" | /usr/xpg4/bin/tail -4 | rev -l 6 5 4 3 -- snip -- All other combinations for "-<number>" are identical between "tail -<number>r" and "tail -<number> | rev -l", too. However this is _not_ true when I use "tail +<number>r" compared to "tail +<number> | rev -l". In that case the output differs: -- snip -- $ print "1\n2\n3\n4\n5\n6" | /usr/xpg4/bin/tail +4r 6 5 4 3 2 $ print "1\n2\n3\n4\n5\n6" | /usr/xpg4/bin/tail +4 | rev -l 6 5 4 -- snip -- Both outputs differ and I belive this is simply a bug in the current SXCE implementation. Question to gatekeepers: How should I handle this issue ? Should we... a) ... treat this as bug and fix it with the upcoming ksh93-integration putback or b) ... make the AST/ksh93 builtin behave _exactly_ as the current SXCE implementation of /usr/bin/tail+/usr/xpg4/bin/tail and fix this bug with a later putback or c) ... declare that this is not a bug and keep the inconsistent behaviour of "tail +<number>r" vs. "tail +<number> | rev -l". AFAIK I would prefer [a] but I have a patch for [b], too. [c] is IMO not really an option since makes option "r" behave in an inconsistent way. ---- Bye, Roland -- __ . . __ (o.\ \/ /.o) roland.mainz at nrubsig.org \__\/\/__/ MPEG specialist, C&&JAVA&&Sun&&Unix programmer /O /==\ O\ TEL +49 641 3992797 (;O/ \/ \O;)
