一次开发中使用过的shell命令

1.时间计算

starttime=`date +'%Y-%m-%d %H:%M:%S'`;
endtime=`date +'%Y-%m-%d %H:%M:%S'`;
start_seconds=$(date --date="$starttime" +%s);
end_seconds=$(date --date="$endtime" +%s);
echo end_seconds-start_seconds

2.获取链接返回的状态码

checkurl='http://www.baidu.com'
curl --connect-timeout 1 -s -w "%{http_code}" -o temp  ${checkurl}

3.while...do，for循环；条件判断if；退出程序exit

while (( `curl --connect-timeout 1 -s -w "%{http_code}" -o temp ${checkurl}` != '200' ))
do
            for i in $(seq 1 20); do echo 'sleep countdown to wait url is ok:'$((20-$i)); sleep 1; done;//倒计时
            endtime=`date +'%Y-%m-%d %H:%M:%S'`;
            start_seconds=$(date --date="$starttime" +%s);
            end_seconds=$(date --date="$endtime" +%s);
            if [[ $((end_seconds-start_seconds)) > 600 ]]; then 
                exit 1
            fi    
done

4.字符串截取和替换

checkurl=${line#*=}    //截取变量line，等号右边的保留
checkurl=${checkurl/${ESMHOST}/sss}   //用sss替换checkurl中的${ESMHOST}

5.文本文件的字符串替换

 文件中所有的abc都替换为aaaaa

sed -i 's#abc#aaaaa#g' ./docker-compose.yml

6.模糊匹配

如果变量包含字符串'register.node.checkurl'

if [[ $line =~ 'register.node.checkurl' ]];then

fi