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# 禁止密码登录 | |
PasswordAuthentication no | |
# 禁止Root登录 | |
PermitRootLogin no | |
# 网开一面 | |
Match Address 172.xx.yy.zz | |
PermitRootLogin yes | |
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> devices=read.table("test.csv",header=TRUE,sep=",") | |
读取数据 | |
> country_table=with(devices,table(country)) | |
计算频率 | |
> as.data.frame(country_table[order(country_table,decreasing=TRUE)]) | |
排序,列显示 | |
> as.data.frame( prop.table(country_table[order(country_table,decreasing=TRUE)])*100) |
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ps -ef 看到对应进程号。 | |
ps p 2664 -L | |
可以看到进程列表(第3列显示当前状态,第三列显示保持当前时间,分钟:秒 格式) | |
2664 3200 ? Sl 104:02 java -XX:-UseBiasedLocking -XX:AutoBoxCacheMax=20000 -XX:+UseConcMarkSweepGC -XX:CMSInitiatingOccupancyFraction=75 -XX:MaxTenuringThreshold=8 -XX | |
2664 3201 ? Sl 103:48 java -XX:-UseBiasedLocking -XX:AutoBoxCacheMax=20000 -XX:+UseConcMarkSweepGC -XX:CMSInitiatingOccupancyFraction=75 -XX:MaxTenuringThreshold=8 -XX | |
2664 3202 ? Sl 103:47 java -XX:-UseBiasedLocking -XX:AutoBoxCacheMax=20000 -XX:+UseConcMarkSweepGC -XX:CMSInitiatingOccupancyFraction=75 -XX:MaxTenuringThreshold=8 -XX |
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慢查询优化: | |
mysql> show variables like "%long%"; //查看一下默认为慢查询的时间10秒 | |
mysql> show variables like "%slow%"; //查看慢查询是否enable | |
mysql> set slow_query_log='ON'; //加上global,不然会报错的。 | |
mysql> set global slow_query_log='ON'; //启用慢查询 | |
[my.cnf] | |
long_query_time = 2 | |
log-slow-queries = /usr/local/mysql/mysql-slow.log |
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$ curl -s "https://get.sdkman.io" | bash | |
$ source "$HOME/.sdkman/bin/sdkman-init.sh" | |
$ sdk version ## 执行上面脚本后,sdk是一个function,加载在内存里 | |
ref:https://sdkman.io/install |
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招商银行 https://app.cmbchina.com/cevs/checkmain.aspx 企业 | |
招商银行 https://app.cmbchina.com/pevs/pccheck.aspx 个人 | |
建设银行 https://b2bstatic.ccb.com/B2Bdzhd.HTM | |
中国银行 https://ebsnew.boc.cn/boccp/elecbillvalidate.html?lan=C | |
工商银行 https://mybank.icbc.com.cn/icbc/perbank/e_bill/ebill_verify_query.jsp?isClose=1 | |
交通银行 http://www.bankcomm.com/BankCommSite/shtml/jyjr/cn/7924/9484/list.shtml?channelId=7158 | |
兴业银行 https://corporatebank.cib.com.cn/firm/cash/receipt/receiptQuery!openPrint.do | |
平安银行 https://ebank.sdb.com.cn/corporbank/validateElectronicBillInput.do | |
浦发银行 http://ebank.spdb.com.cn/net/eBillValidateInput.do |
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cat -n file | sort -k2 | uniq -f1 | sort -k1 | cut -f2- | |
How it works: | |
On a GNU system, cat -n will prepend the line number to each line following some amount of spaces and followed by a <tab> character. cat pipes this input representation to sort. | |
sort's -k2 option instructs it only to consider the characters from the second field until the end of the line when sorting, and sort splits fields by default on white-space (or cat's inserted spaces and <tab>). | |
When followed by -k1n, sort considers the 2nd field first, and then secondly—in the case of identical -k2 fields—it considers the 1st field but as sorted numerically. So repeated lines will be sorted together but in the order they appeared. | |
The results are piped to uniq—which is told to ignore the first field (-f1 - and also as separated by whitespace)—and which results in a list of unique lines in the original file and is piped back to sort. |
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ⓆⓇⓅⓨⓣⓗⓞⓝ | |
ⓆⓇⓅⓆⓇⓈⓉⓊⓋⓌⓍⓎⓏ |
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每笔交易是有顺序的吗? | |
每个新生成的区块里包含的交易是一样的吗? | |
何时决定交易可以打包生成区块? | |
如何在链表的终端提取一个数据,比如账户值 ? 需要进行整个链条的校验吗? | |
一个合约对于某些代码功能比如网络,数学库等怎么支持 | |
大型合约怎么部署,依赖的js库有变动怎么办 |
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