source: CMT/HEAD/mgr/cmt_linux_version.sh

# Determine the Linux distribution and version that is being run.
#

export LC_ALL=C
# Check for GNU/Linux distributions
if [ -f /etc/SuSE-release ]; then
    DISTRIBUTION="suse"
    VERSION=`sed  -n '/VERSION/{s#[^0-9]##gp;q}' /etc/SuSE-release`
elif [ -f /etc/UnitedLinux-release ]; then
    DISTRIBUTION="united"
    VERSION=`cat /etc/UnitedLinux-release`
elif [ -f /etc/debian_version ]; then
    DISTRIBUTION="debian"
    VERSION=`cat /etc/debian_version`
    if [ ${VERSION} = "testing/unstable" ]; then
        # The debian testing/unstable version must be translated into
        # a numeric version number, but no number makes sense so just
        # remove the version all together.
        VERSION=""
    fi
elif [ -f /etc/redhat-release ]; then
    read a </etc/redhat-release
    case "$a" in
        Red*Hat*Enterprise*Linux*)
            DISTRIBUTION=rhel
            ;;
        Red*Hat*Linux*)
            DISTRIBUTION=rh
            ;;
        CERN*E*Linux*)
            DISTRIBUTION=cel
            ;;
        Scientific*Linux*CERN*)
            DISTRIBUTION=slc
            ;;
        Scientific*Linux*)
            DISTRIBUTION=sl
            ;;
        Fedora*)
            DISTRIBUTION=fedora
            ;;
        *)
            DISTRIBUTION=slc
            ;;
    esac
    VERSION=""
    release=
    for w in `echo $a`; do
        case "$w" in
            release)
                release=y
                ;;
            *)
                if [ "$release" ]; then
                    VERSION=$w
                    release=
                fi
                ;;
        esac
    done
#     while [ -n "$a" ]; do
#       t="${a#?}"              # all but first char of $a
#       c=${a%"${t}"}           # first char of $a
#       a="${t}"                # remove first char from $a
#       case "$c" in
#           [0-9])
#           VERSION="${VERSION}${c}"
#           ;;
#       esac
#     done
    case "$VERSION" in
        70|71|72)
            VERSION=73
            ;;
    esac
    [ "$VERSION" ] || VERSION='00'
else
    DISTRIBUTION="unknown"
    VERSION='00'
fi

echo ${DISTRIBUTION}-${VERSION}