shell脚本，获取执行结果

Shell获取上一个命令执行结果，传递到下个命令执行,手写shell脚本

示例：

#!/bin/bashecho "list gps image..."docker images|grep gpsif [ $? -eq 0 ]; then echo "success..."ret1=`docker images|grep gps`num=0for i in $ret1; donum=`expr $num + 1`if [ $num == 3 ];thenecho "找到容器ID= $i "ret2=`docker rmi -f $i`if [ $? -eq 0 ];thenecho "删除容器 ${i} 成功"elseecho "删除容器 ${i} 失败"exit 1fiexit 1fidoneecho $numelseecho "failed..."exit 1fiunset numexit 1