Programming VIP

When we write a program, we often need to judge the execution result of the previous step, so the judgment needs to be realized by using if statement. if statement is mainly used for judgment in our program. 1, if syntax 1.1 single branch if if condition;then Command to execute 1 Command to execute 2 Command to execute 3 . ...

shell programming shell overview The parsers provided by Linux are [root@pihao01 ~]# cat /etc/shells /bin/sh /bin/bash /usr/bin/sh /usr/bin/bash [root@pihao01 ~]# Relationship between bash and sh [root@pihao01 bin]# ll |grep bash -rwxr-xr-x. 1 root root 1219248 Nov 9 2019 bash lrwxrwxrwx. 1 root root 4 Nov 9 2019 sh ...

Preface In some complex Linux maintenance tasks, a large number of repetitive inputs and interactions are time-consuming and error-prone. Writing a proper shell script program can accomplish a series of maintenance tasks in batch and automate, greatly reducing the burden of administrators. 1. An overview of Shell scripts 1. What is a ...

Catalog Use shell module in rendering process (UI interface) Use shell module in application menu Use shell module in context menu Disable Menu Items !! Dynamic Generation Menu Disable menu: enabled:!! filePath Dynamic startup menu: createContextMenu().popup(); Application Menu ...

1 Question Android 10.0 devices connect to another device through a hotspot name and password to specify a hotspot, but they still cannot communicate with each other and the network is unreachable. The Android 10.0 device connects another set of designated hotspots by hotspot name and password. I'm using the official API and can refer to this ...

Note: This paper is based on MongoDB 4.2.6 1. Delete Delete a document > db.bb.find().pretty() { "_id" : ObjectId("5ed6549830571733ccb3d678"), "jordan" : 23, "haha" : "ending" } { "_id" : ObjectId("5ed6549830571733ccb3d679"), "kobe" : 24, "haha" : "ending" } > db.bb.remove({jordan: 23}) ...

What is panda? pandas is a NumPy based tool, which is created to solve data analysis tasks. pandas incorporates a large number of libraries and some standard data models, providing the tools needed to efficiently operate large datasets. pandas provides a large number of functions and methods that enab ...

1. Count the number of files under / var/log. //find /var/log -type f | wc -l; 2. How to output the running result of F1.txt file to F2.txt? // ./F1 > F2.txt shF1 > F2.txt; 3. Write a script to judge which ip addresses are currently online in the 192.168.1.0/24 network, and ping the gen ...

What is thread When it comes to threads, we should first understand what a process is. You should be familiar with this picture. The programs we see running separately are independent processes, and the processes are independent of each other. The 360 browser and Baidu cloud disk in the above figure are all independent processes. So what are th ...

    1, Foreword By Jack Cui After the learning of the last two articles, Python crawler takes three steps: request initiation, data parsing and data saving. Have you mastered them? Are they entry-level crawlers? No, it's not enough! Only mastering these skills can only be regarded as layman level. Today, let's continue to learn how to clim ...