#! /bin/bash
# inpath -- 驗(yàn)證指定程序是否有效，或者能否在PATH目錄列表中找到

in_path()
{
        cmd=$1  ourpath=$2      result=1
        oldIFS=$IFS IFS=":"
        for directory in $ourpath
        do
                if [ -x $directory/$cmd ] ; then
                        result=0
                fi
        done

        IFS=$oldIFS
        return $result
}

checkForCmdInPath()
{
        var=$1
        if [ "$var" != "" ] ; then
                if [ "${var:0:1}" = "/" ] ; then
                        if [ ! -x $var ] ; then
                                return 1
                        fi
                elif ! in_path $var "$PATH"; then
                        return 2
                fi
        fi


}


if [ $# -ne 1 ] ; then
        echo "Usage: $0 command" >&2
        exit 1
fi

checkForCmdInPath "$1"

case $? in
        0 ) echo "$1 found in PATH" ;;
        1 ) echo "$1 not found or not executable" ;;
        2 ) echo "$1 not found in PATH" ;;
esac

exit 0

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