Shell脚本实现ftok函数

#!/bin/sh
let key=0
function ftok() {
    pathname=$1;
    proj_id=$2;

    str_st_ino=`stat --format='%i' "${pathname}" 2>/dev/null`;
    str_st_dev=`stat --format='%d' "${pathname}" 2>/dev/null`;
    if [ "x${str_st_ino}" = "x" -o "x${str_st_dev}" = "x" ] ; then
        return 1;
    fi

    let st_ino=${str_st_ino}
    let st_dev=${str_st_dev}

    # 注意这里的位操作运算符需要加转义符
    let key1=${st_ino}\&16#FFFF
    let key2=${st_dev}\&16#FF
    let key2=${key2}\<\<16
    let key3=${proj_id}\&16#FF
    let key3=${key3}\<\<24
    let key=${key1}\|${key2}
    let key=${key}\|${key3}
}

function echohelp(){
    echo "ftok generator"
    echo "Usage:ftok pathname projid"
    exit 5
}

if [ $# -ne 2 ] ; then
    echohelp
fi

sPathName=$1
let nProjectID=$2

if [ "${sPathName:0:1}" != "/" ] ; then
    sPathName=${PWD}/${sPathName}
fi

if ! test -f ${sPathName} ; then
    echo "No File Found![${sPathName}]"
    exit 4
fi

ftok "${sPathName}" "${nProjectID}"
echo ${key}