shell 执行回调脚本 与 exec执行脚本获取不到输出问题

执行脚本（假设命令都在变量 xxx 中, xxx 为 ping baidu.com -c 3）：有

eval $xxx

exec $xxx

${xxx}

而获取输出有：

1：输出到变量 log=${xxx}

2：输出到文件 eval $xxx >/tmp/log.log 2>&1

#!/bin/bash

# init
touch_log="/tmp/`cat /proc/sys/kernel/random/uuid`.log"

# $1 exec type 1:ok, 2:error
exec_out() {
   curl_get="curl $RUN_HOST/base/exec -F \"log=@$touch_log\" -F \"state=$1\""
   for i in ${RUN_JSON//&/ }; do curl_get+=" -F \"${i//\"/\\\"}\""; done
   echo $curl_get > /tmp/curl.log
   eval $curl_get
   rm -Rf $touch_log
}

help() {
   echo "Usage:"
   echo "exec.sh [options] <mainclass> [args]"
   echo ""
   echo "where options include"
   echo "    -d:<exec file path> "
   echo "        Execute directory. If it is not filled in. the default is /"
   echo "    -c:<exec code>"
   echo "        Exec command executed"
   echo "    -j:<exec json>"
   echo "        Command return json"
   echo "    -h:<get url host>"
   echo "        get host"
   exit -1
}

while getopts 'd:c:t:j:h:' opt; do
   case $opt in
      d) RUN_DIR="$OPTARG";;
      c) RUN_CODE="$OPTARG";;
      j) RUN_JSON="$OPTARG";;
      h) RUN_HOST="$OPTARG";;
      ?) help;;
   esac
done


if [ "$RUN_CODE" != "" ]; then
    source /etc/profile
    eval $RUN_CODE > $touch_log 2>&1
    if [ $? -eq 0 ]; then
        exec_out 1
    else
        exec_out 2
    fi
else
    echo "code nil" > touch_log
    exec_out 2
fi

# delete run file
if [[ "$0" != "/" || ${#0}>2 ]]; then
    rm -Rf $0
fi