flex-2.5.31: `head -1' is obsolete, use `sed 1q' or `head -n1' instead

[Jim Meyering]

Hi,

Thanks for working on flex!
Here's a little patch that you may soon find useful.

But first 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 know 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  head: `-1' option is obsolete; use `-n 1'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]

Even if the coreutils programs you use were built on
a system that doesn't claim conformance with that version
of POSIX, you can instruct the affected tools to adhere to
the newer standard by setting _POSIX2_VERSION=200112 in
your environment.  That's what I do, and that's how I noticed
the failure reported below.
---------------------------

I'm using `head' from the coreutils-5.0.90 package
and have _POSIX2_VERSION=200112 set in my environment.

When I ran ./configure, I got this:

  ...
  checking if /usr/bin/indent is GNU indent... head: `-1' option is obsolete; 
use `-n 1'
  Try `head --help' for more information.
  no
  configure: WARNING: /usr/bin/indent does not appear to be GNU indent.
  ...

Here is a proposed patch.
If you're concerned about some ancient version of head that doesn't
know about the -n option, you could replace it with `sed 1q'.

2003-08-12  Jim Meyering  <address@hidden>

        * configure.in: Use `head -n 1' in place of obsolete `head -1'.

--- configure.in.~1~    2003-08-12 06:08:26.000000000 +0200
+++ configure.in        2003-08-12 06:08:42.000000000 +0200
@@ -48,7 +48,7 @@ AC_PATH_PROG(INDENT, indent, indent)
 dnl if INDENT is set to 'indent' then we didn't find indent
 if test "$INDENT" != indent ; then
    AC_MSG_CHECKING(if $INDENT is GNU indent)
-   if $INDENT --version 2>/dev/null | head -1|grep "GNU indent" > /dev/null ; 
then
+   if $INDENT --version 2>/dev/null | head -n 1|grep "GNU indent" > /dev/null 
; then
       AC_MSG_RESULT(yes)
    else
       AC_MSG_RESULT(no)