I had the same problem and came across a solution
that gcc uses. For various reasons this is
expressed as a bash script and a more recent
version is probably abailable. I leave the conversion
to Perl as an exercise for the reader:
# Short circuit this function if we know which system we are on
if [ $OS_SYSTEM_REALLY ]; then
echo "${OS_SYSTEM_REALLY}"
return
fi
# First get the values for this machine
# Code lifted from config.guess in the gcc software
OS_UNAME_M=`(uname -m) 2>/dev/null` || OS_UNAME_M=unknown
OS_UNAME_S=`(uname -s) 2>/dev/null` || OS_UNAME_S=unknown
OS_UNAME_R=`(uname -r) 2>/dev/null` || OS_UNAME_R=unknown
OS_UNAME_V=`(uname -v) 2>/dev/null` || OS_UNAME_V=unknown
OS_UNAME="${OS_UNAME_M}:${OS_UNAME_S}:${OS_UNAME_R}:${OS_UNAME_V}"
# Note: order is significant - the case branches are not exclusive
+.
case "${OS_UNAME}" in
sun4*:SunOS:5.[012345]*:*)
echo "sol24"
return ;;
sun4*:SunOS:5.[6789]*:*)
echo "sol26"
return ;;
sun4*:SunOS:[7891]*:*)
echo "Unknown Solaris version" >&2
echo "Try setting \$OS_SYSTEM_REALLY to sol26" >&2
echo "unknown"
return ;;
sun4*:SunOS:*:*)
echo "sun"
return ;;
*:AIX:1:4)
echo "aix41"
return ;;
*:IRIX*:5.*:*)
echo "sgi"
return ;;
*:IRIX*:6.[2345]:*)
echo "irix62"
return ;;
9000/[78]??:HP-UX:*:*)
echo "hp"
return ;;
i[345678]86:Linux:*:*)
echo "linux"
return ;;
sparc:Linux:*:*)
echo "ulinux"
return ;;
*:*:*:*)
# If we get here then we have something weird
echo "Unknown system \"${OS_UNAME}\"" >&2
echo "Try setting \$OS_SYSTEM_REALLY to one of sun, sol, h
+p etc" >&2
echo "unknown"
return ;;
esac