Posts tagged with “tips”

Git Tips: Remove tracking branches no longer on remote

My colleage Joe asked me tonight, "how to remove those branches that no longer exist on remote?"

In short, you have two options

  1. run git remote prune origin at times
  2. run git config --global fetch.prune true command to config your git to delete those branches every time when you run git fetch

I prefer the second option, how about you?

Reference

MySQL: Delete All Duplicate Rows Except the Earliest One in One SQL

You want to add a unique index to a table, and unfortunately, there are already many duplicate rows in it. Manually find and delete these rows is time-wasting and error-prone. So why won't we just write one SQL statement and quickly resolve it?

First try, I wrote the following statement, and it won't work: 

DELETE FROM PromotionSkus A 
WHERE 
	A.SkuId IN (SELECT SkuId FROM PromotionSkus B GROUP BY B.SkuId HAVING COUNT(B.SkuId) > 1) 
	AND 
	A.Id NOT IN (SELECT MIN(Id) FROM PromotionSkus C GROUP BY C.SkuId HAVING COUNT(C.SkuId) > 1);

AND this one below works!

DELETE FROM PromotionSkus A
WHERE 
	A.Id NOT IN (SELECT Id FROM (SELECT MIN(Id) AS Id, COUNT(SkuId) AS Total FROM PromotionSkus GROUP BY SkuId HAVING Total > 1) AS B)
	AND 
	A.SkuId IN (SELECT SkuId FROM (SELECT SkuId FROM PromotionSkus GROUP BY SkuId HAVING COUNT(SkuId) > 1) AS C);

The reason is well explained in this brilliant article.

Another mysql tip: using mysqldump export a table with one line one row. 

mysqldump --databases YourDataBaseName --tables YourTableName --skip-extended-insert

Why do we need that? It is much easier to compare !

Git Tips

解决git 命令行把中文文件名显示成 \343\200\212类似乱码的问题

git config --global core.quotepath off

将变更加入缓冲区，但不加入空白（空格、制表符或者换行符）的变更

git diff -w | git apply --cached --ignore-whitespace

Reference

git diff 时排除掉某些不想看的文件

git diff -- . ':(exclude)db/irrelevant.php' ':(exclude)db/irrelevant2.php'

删除远端分支

git push origin --delete branchname

嫌打字麻烦的，可以使用以下简写命令

git push origin :branchname

发现文件丢了不知道谁删的，比如 yarn.lock , 用下面这个命令

git log -p -- yarn.lock

设置总是push到远端的同名分支，从此再也不用如此麻烦的敲 git push -u origin theSameBranchName，你只管 git push 就好！

git config --global push.default current

更多的技巧请访问我的 GotGit 群组

Using sed to insert a line after several lines after the match line

最近一直在写 .net core，它有诸多优点我且不提，我实在头痛于手写注入服务时的模式化代码，因此动了心思要写个小脚本帮我自动化一些事情。我的想法是告诉我要加入的 ServiceName， 指定一个 Controller然后脚本自动在这个 Controller 里声明一个 private readonly 属性，自动修改类的construction 函数，自动注入这个服务，并在construction 函数体写上 _serviceName = serviceName;

在第一步，注入 private readonly 属性那里，我就绊了个跟头。用 sed 匹配到某行，在它之前，或者之后插入数据是简单的。但我匹配到 public class xxxController 这行之后是单独一行 {，而我要加的变量要放到 {这行之后。网上一通搜索，试图找到定位到某行之后N行的命令，然而并没有这样的命令。然而功夫不负有心人，我最后还是找到了一个解决方案，那就是

sed '/pattern/!b;n;n;i\something'

具体解释见 Reference

ubuntu 20.04 手工生成通配符ssl证书

其实很简单，但因为网上有流传很广的教程并不适用于最新的 ubuntu 20.04，造成我也走了一点弯路。 certbot-auto 官方已停止维护，但网上广为流传的教程仍然推荐使用 certbot-auto 来生成证书。这是问题的根源。正确的姿势是这样的

sudo apt install certbot
sudo certbot certonly --manual -d *.yourdomain.com -d youdomain.com --preferred-challenges dns-01 --server https://acme-v02.api.letsencrypt.org/directory

照提示一步一步来就好了。是不是超级简单？