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  Install and setup vsftpd on AWS server

When developing websites, frequently we may need to upload source codes to the remote server. To ease of thew work, many website developers set up FTPs to upload the files. This post is a tutorial on how to install and setup vsftpd on a server. vsftpd is a very popular FTP service on Unix-like systems. Open command terminal, then install the vftpd by issuing command yum install vsftpd or sudo apt-get install vsftpd After installing the vsftpd, the config file needs to be updated based on the ope...

   FTP,vsftpd,AWS,Passive,Active     2015-02-02 02:20:27

  Reset submodule to checkout state in git

Sometimes there would be a submodule or some submodules within one git repository, in some cases the submodule may be out of sync with the checkout state as some files in submodule may be changed unexpectedly. How to reset the submodule to be the same as the original checkout state? Let's take an example that we have a git repository A and there is a submodule called ruby-gems under it. Assuming the submodule at remote origin has commit a. And on our local environment, the repository A has a la...

   GIT RESET,GIT SUBMODULE     2020-09-05 08:30:57

  Some frequently used ES6 code snippets

Below are a list of ES6 code snippets which are used frequently. Hope that it will be helpful. 1. Shuffle array elements let arr = [67, true, false, '55'] arr = arr.sort(() => 0.5 - Math.random()) console.log(arr) // [ '55', 67, false, true ] 2. Remove characters which are not numbers const str = 'xieyezi 23213 is 95994 so hansome 223333' const numbers = str.replace(/\D/g, '') console.log(numbers) // 2321395994223333 3. Reverse sequence or words const sentence = 'xieyezi js so handsome, lol.'...

   JAVASCRIPT,ES6,CODE SNIPPET,TIPS     2022-04-10 07:56:07

  What does session_destroy() do in PHP?

In PHP manual, the description for session_destroy() function is : session_destroy() destroys all of the data associated with the current session. It does not unset any of the global variables associated with the session, or unset the session cookie. To use the session variables again, session_start() has to be called. I am confused about this description. If this function destroys all session data, then why the global variables associated with the session are not unset? Why can we u...

   session_destroy,session_start     2013-08-31 09:59:05

  How to do pprof for gRPC service

gRPC is a RPC framework based on HTTP and is frequently used for communications among micro service inside the same organization network. However,  the service functions cannot be accessed via normal HTTP URL as it's not a WEB framework. In this case, how to do pprof on a gRPC service? The trick is starting a HTTP server asynchronously while starting the gRPC service. This HTTP server can be accessed to run prrof debug. go func(){ http.ListenAndServe(":10001", nil) }() Since it uses the de...

   GOLANG,PPROF,GRPC     2021-01-29 23:11:33

  Write HTML easily with Emmet and Haml

Writing HTML codes is very boring and tedious as it has many tags and it's static. One solution is to use template, filling content based on other's skeleton. One another solution is high speed writing. We can write HTML codes with Emmet and Haml. These two ways have similar functions but with different characteristics. Haml is based on Ruby, so when working on Ruby/Rails projects, we recommend to use Haml, otherwise we recommend to use Emmet. 1. Emmet Emmet is a editor plugin, the official webs...

   HTML,Emmet,Haml     2013-06-11 19:46:02

  JavaScript tips both novice and veteran developers can benefit from

In this post, we will share some less known but powerful JavaScript tips which can benefit both novice and veteran JavaScript developers. 1. Truncate array with array length We all know that object are passed by reference in JavaScript, but we may be bitten by this rule. Please check below example: var arr1 = arr2 = [1, 2, 3]; //Change arr1 arr1 = []; // arr2 will still be [1,2,3] arr1 and arr2 point to the same array [1,2,3] initially, later when arr1 repoints to [], the reference to arr2 is n...

   JavaScript,Array,push     2013-08-21 04:09:10

  Some tricks and tips for using for range in GoLang

GoLang provides two major ways to loop through elements of array, slice and map. They are for and for range. Many people find that for range is very convenient when don't care about the index of the element. In this post, some tricks and tips would be talked about regarding for range. 1. Loop and get pointer of each element Assume there is a code snippet like below which is to get the pointer of each element in an array and create a new array with the corresponding pointer. arr := [2]int{1, 2} r...

   POINTER,FOR LOOP,GOLANG,FOR RANGE     2020-03-08 01:07:00

  The Ultimate Guide to Implement Function Overloading in Python

Introduction When it comes to function overloading, those who have learned Java should be familiar with it. One of the most common uses is logging, where different overloaded functions are called for different parameters. So, how can we implement function overloading in Python? Concept of Overloading Function overloading allows multiple functions with the same name to exist within the same scope, but with different parameter lists. Although many programming languages (like Java and C++) support ...

   GUIDE,JAVA,OVERLOADING,PYTHON     2024-11-14 22:29:17

  A possible way to recover deleted files on Linux

Last week I was generating a MD5 sum for an virtual machine image on one OpenNebula server: # ls -l test.img -rw-r--r-- 1 root root 10486808576 Oct 12 02:21 test.img # md5sum test.img At the same time I was clearing the files on the server on another terminal and deleted the above image file mistakenly with : # rm test.img Since this image file is 10GB, it took some time to remove this file from the server, so I used the Ctrl+Z command to suspend the remove command. [1]+ Stopped ...

   Linux,File,Recovery     2013-11-26 07:03:37

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