Re: POSIX conformance in coreutils

[Peter Stephenson <pws@xxxxxxx>]

Vin Shelton wrote:
> I checked and I do not have POSIXLY_CORRECT set.  Here's what the
> 'Standards conformance' section of the coreutils info says:

It doesn't look like we can expect much sense, then.

Here is a more heavyweight change.

Index: Test/ztst.zsh
===================================================================
RCS file: /cvsroot/zsh/zsh/Test/ztst.zsh,v
retrieving revision 1.20
diff -u -r1.20 ztst.zsh
--- Test/ztst.zsh	12 Jan 2005 10:32:20 -0000	1.20
+++ Test/ztst.zsh	12 Jan 2005 15:56:50 -0000
@@ -28,9 +28,6 @@
 [[ -n $LC_COLLATE ]] && LC_COLLATE=C
 [[ -n $LANG ]] && LANG=C
 
-# POSIXLY_CORRECT can cause spurious error messages with "tail -<num>".
-unset POSIXLY_CORRECT
-
 # Set the module load path to correspond to this build of zsh.
 # This Modules directory should have been created by "make check".
 [[ -d Modules/zsh ]] && module_path=( $PWD/Modules )
@@ -60,6 +57,33 @@
 
 integer ZTST_testfailed
 
+# This is POSIX nonsense.  Because of the vague feeling someone, somewhere
+# may one day need to examine the arguments of "tail" using a standard
+# option parser, every Unix user in the world is expected to switch
+# to using "tail -n NUM" instead of "tail -NUM".  Older versions of
+# tail don't support this.
+tail() {
+  emulate -L zsh
+
+  if [[ -z $TAIL_SUPPORTS_MINUS_N ]]; then
+    local test
+    test=$(echo "foo\nbar" | command tail -n 1 2>/dev/null)
+    if [[ $test = bar ]]; then
+      TAIL_SUPPORTS_MINUS_N=1
+    else
+      TAIL_SUPPORTS_MINUS_N=0
+    fi
+  fi
+
+  integer argi=${argv[(i)-<->]}
+
+  if [[ $argi -le $# && $TAIL_SUPPORTS_MINUS_N = 1 ]]; then
+    argv[$argi]=(-n ${argv[$argi][2,-1]})
+  fi
+
+  command tail "$argv[@]"
+}
+
 # The source directory is not necessarily the current directory,
 # but if $0 doesn't contain a `/' assume it is.
 if [[ $0 = */* ]]; then


-- 
Peter Stephenson <pws@xxxxxxx>                  Software Engineer
CSR PLC, Churchill House, Cambridge Business Park, Cowley Road
Cambridge, CB4 0WZ, UK                          Tel: +44 (0)1223 692070


**********************************************************************
This email and any files transmitted with it are confidential and
intended solely for the use of the individual or entity to whom they
are addressed. If you have received this email in error please notify
the system manager.

This footnote also confirms that this email message has been swept by
MIMEsweeper for the presence of computer viruses.

www.mimesweeper.com
**********************************************************************