check Xcode version

gistfile1.sh

# http://stackoverflow.com/questions/4023830/bash-how-compare-two-strings-in-version-format/4025065#4025065
# 0: =, 1: >, 2: <
vercomp () {
    if [[ $1 == $2 ]]
    then
    return 0
    fi
    local IFS=.
    local i ver1=($1) ver2=($2)
    # fill empty fields in ver1 with zeros
    for ((i=${#ver1[@]}; i<${#ver2[@]}; i++))
    do
        ver1[i]=0
    done
    for ((i=0; i<${#ver1[@]}; i++))
    do
        if [[ -z ${ver2[i]} ]]
        then
            # fill empty fields in ver2 with zeros
            ver2[i]=0
        fi
        if ((10#${ver1[i]} > 10#${ver2[i]}))
        then
            return 1
        fi
        if ((10#${ver1[i]} < 10#${ver2[i]}))
        then
            return 2
        fi
    done
    return 0
}

REQUIRED_VERSION=6.1
VERSION=`xcodebuild -version | head -n 1 | cut -d ' ' -f 2`
vercomp $VERSION $REQUIRED_VERSION
if [[ $? == 2 ]]; then
    # http://briksoftware.com/blog/?p=120
    echo "error: required Xcode version ${REQUIRED_VERSION}"
fi

gistfile2.sh

if [[ $XCODE_VERSION_MINOR < 0610 ]]; then
    echo "error: required Xcode version 6.1"
fi