Programmer Think

I. File Descriptors File Descriptor (fd): A file descriptor is a non-negative integer. When an existing file or a new file is opened, the kernel returns a file descriptor. Reading and writing a file also requires the use of a file descriptor to access the file. It is also the file record table that the kernel maintains for each process ...

Foreword... 2 I. Conditional Selection and Judgment (if, case). 2 1.1 if statement usage and examples 1.2 case usage and examples II. Circular Sentences... 7 2.1 for cycle... 8 2.2 while cycle... 10 2.3 until cycle * 12 2.4 select cycle... 13 2.5 Cyclic Supplement.. 14 2.5.1 Loop Control Statement continue&break.14 2.5.2 Loop Control Comma ...

1. Command Segmentation in Bash Each command or sequence of commands is separated by semicolons (;) or newline characters (\n). $ cmd1 ;cmd2  Equivalent to $cmd1 $cmd2 2. Terminal printing echo and printf Double quotation marks - variable name replacement; special character order escape character () - e takes effect Single quotation ma ...

20.27 Distribution System Introduction   Distribution system, in what scenarios For example, companies are doing more and more business. The programming language of their website or App is PHP, so to run this environment, PHP code needs to configure the environment of LAMP or LNMP, and code needs to be uploaded to the server, which is a web ...

Foreword: Yesterday I learned about rest-framework serialization, so I wrote a blog record. Official website: http://www.django-rest-framework.org/tutorial/1-serialization/#working-with-serializers.   Front-end and back-end separation: Front-end development and back-end development are separated. The implementation of this scheme is to use AP ...

For Android programmers, adb is frequently used in their daily work. Now, we summarize the commonly used adb commands in their work, which is convenient for inquiry and also for your reference. Viewing application memory usage, power consumption, startup time, wakelock, running monkey commands played a small role in previous application per ...

There are often situations where cmd is needed in a folder, such as running a script. Here are several ways to do this. Take the following directory operations as an example: Mode 1: Common cd commands The cd command is the most common way we use it: Win+R opens the cmd window, which is displayed as follows by default (non-administrator mo ...

Algorithms Series 15 Days Quick - Seven Classic Sorting on the Third Day From: http://blog.csdn.net/m13666368773/article/details/7506678 Today I'm going to talk about the last three sorts of sorting: direct insertion sort, Hill sort and merge sort.   Direct insertion sort: This sort is quite understandable. A real example is that we fight ag ...

Troubleshooting Gitlab-runner build failures: Causes of the problem: Automated build based on gitlab ci. job runs with errors when merge_requests request is initiated to start building. It is officially recommended to upgrade gitlab-runner version. Build runs with errors after version upgrade. The errors are as follows: Running with gitlab-run ...

0x00 Preface Preposition Thank you for the total cultivation of eggs. This article was first published in spring and autumn. I do not agree to prohibit reprinting. Explain First of all, I would like to write NDK, but let's go through this process first. This process is essential. Secondly, RMB is really a good th ...