linux shell 字符串拼接方法

CROSS_COMPILE=arm-openwrt-linux-muslgnueabi-

echo $CROSS_COMPILE

方法1：

    test1=$(echo $CROSS_COMPILE)gcc

    echo $test1

方法2：

    test2=${CROSS_COMPILE}gccabc

    echo $test2

不能这样写 "${TN3RD_$(echo ${library} | tr '[a-z]' '[A-Z]')_SUPPORT}"

直接写：

if [ "$library" == "zlib" ]then

echo "${library} is included"

fi

testt=$(date +%Y-%m-%d)

date2="14/08/12"

test=20

testtt="${test}${date2}"

time1=$(date +%s -d "$testt" )

time2=$(date +%s -d "$testtt" )

time=$(($time1-$time2))

echo $time

改成引号，去掉括号！！

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