For the benefit of the SRFI-22 discussion list, here are results sent
to me by Alan Bawden.  It confirms that SunOS 4.1.4.1 has a 32
character limit.  Otherwise, both "#! /usr/bin/env ..." and
"#!/usr/bin/env ..." seem to work on all platforms tested up to now.

Marc

-------------------------------------------------------------------------------

The SunOS 4.1.4.1 result is the most interesting...

======= FreeBSD 3.4 =======

testscript 1.0
FreeBSD snowview.camellia.org 3.4-RELEASE FreeBSD 3.4-RELEASE #8: Sat Oct  7 00:11:55 EDT 2000     xxxxxx@snowview.camellia.org:/usr/src/sys/compile/HELOISE  i386
Wed May 23 02:05:31 EDT 2001
-------------------- ./script1
#! /usr/bin/env cat
-------------------- ./script2
#!/usr/bin/env cat
-------------------- ./script3
-------------------- ./script4
-------------------- ./script5
./script5: not found
-------------------- ./script6
./script6: not found
-------------------- ./script7
-------------------- ./script8

======= SunOS 4.1.4.1 =======

testscript 1.0
SunOS mc 4.1.4 1 sun4c
Wed May 23 02:18:53 EDT 2001
-------------------- ./script1
#! /usr/bin/env cat
-------------------- ./script2
#!/usr/bin/env cat
-------------------- ./script3
No such file or directory: ./script3-helper
-------------------- ./script4
No such file or directory: ./script4-helper-
-------------------- ./script5
#! /bin/env cat
-------------------- ./script6
#!/bin/env cat
-------------------- ./script7
No such file or directory: ./script7-helper-fil
-------------------- ./script8
No such file or directory: ./script8-helper-file

======= NetBSD 1.5 =======

testscript 1.0
NetBSD bronze.lcs.mit.edu 1.5 NetBSD 1.5 (GENERIC) #1: Wed Nov 29 00:29:52 MET 2000     xxxxxx@flambard:/usr/src/sys/arch/sparc/compile/GENERIC sparc
Wed May 23 02:15:46 EDT 2001
-------------------- ./script1
#! /usr/bin/env cat
-------------------- ./script2
#!/usr/bin/env cat
-------------------- ./script3
-------------------- ./script4
-------------------- ./script5
./script5: not found
-------------------- ./script6
./script6: not found
-------------------- ./script7
-------------------- ./script8

======= Irix =======

testscript 1.0
IRIX64 world 6.2 03131016 IP19
Wed May 23 06:17:49 GMT 2001
-------------------- ./script1
#! /usr/bin/env cat
-------------------- ./script2
#!/usr/bin/env cat
-------------------- ./script3
#! /usr/bin/env cat
#! /usr/bin/env ./script3-helper-file890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567
-------------------- ./script4
#!/usr/bin/env cat
#!/usr/bin/env ./script4-helper-file7890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567
-------------------- ./script5
#! /bin/env cat
-------------------- ./script6
#!/bin/env cat
-------------------- ./script7
#! /bin/env cat
#! /bin/env ./script7-helper-file4567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567
-------------------- ./script8
#!/bin/env cat
#!/bin/env ./script8-helper-file34567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567

======= SunOS =======

testscript 1.0
SunOS shell3 5.8 Generic_108528-05 sun4u sparc SUNW,Ultra-60
Wed May 23 02:19:55 EDT 2001
-------------------- ./script1
#! /usr/bin/env cat
-------------------- ./script2
#!/usr/bin/env cat
-------------------- ./script3
#! /usr/bin/env cat
#! /usr/bin/env ./script3-helper-file890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567
-------------------- ./script4
#!/usr/bin/env cat
#!/usr/bin/env ./script4-helper-file7890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567
-------------------- ./script5
#! /bin/env cat
-------------------- ./script6
#!/bin/env cat
-------------------- ./script7
#! /bin/env cat
#! /bin/env ./script7-helper-file4567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567
-------------------- ./script8
#!/bin/env cat
#!/bin/env ./script8-helper-file34567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567

======= Linux (Debian) =======

testscript 1.0
Linux suhr 2.2.17 #2 SMP Thu Sep 14 21:01:22 EDT 2000 i686 unknown
Wed May 23 02:25:33 EDT 2001
/nfs/raid/home/alan/testscript-tmp
-------------------- ./script1
#! /usr/bin/env cat
-------------------- ./script2
#!/usr/bin/env cat
-------------------- ./script3
#! /usr/bin/env cat
#! /usr/bin/env ./script3-helper-file890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567
-------------------- ./script4
#!/usr/bin/env cat
#!/usr/bin/env ./script4-helper-file7890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567
-------------------- ./script5
sh: ./script5: No such file or directory
-------------------- ./script6
sh: ./script6: No such file or directory
-------------------- ./script7
sh: ./script7: No such file or directory
-------------------- ./script8
sh: ./script8: No such file or directory

======= End =======