Introduction to test
The test command test is used to form an expression that is judged by the conditional judgment statement if-else.
For example, you can tell if a file exists and what features it has (is it readable?Writable?Executable?Block file?)Wait.
The test command test has three syntax formats:
[ EXPRESSION ]
[[ EXPRES ...
Posted on Tue, 07 Jan 2020 21:49:09 -0500 by joespenceley
_Memcached is a high-performance distributed memory object caching system for dynamic Web applications to reduce database load.It improves the speed of dynamic, database-driven Web sites by caching data and objects in memory to reduce the number of times the database is read.Memcached is based on a hashmap that stores key/value pairs. ...
Posted on Tue, 07 Jan 2020 13:25:06 -0500 by Qense
1. Main contents of docker
(1) . docker is a cs architecture
(2) . docker: image container warehouse network storage monitoring
(3) . docker is a software packaging technology
2.docker image basic command
1.docker search Nginx (search image)
[root@docker03 ~]# docker search nginx
NAME DESCRIPTION ...
Posted on Tue, 07 Jan 2020 11:06:59 -0500 by bliss322
Generation of demand (regional renewal)
Our company is an e-commerce platform. Its main products include an intelligent water dispenser product, and each intelligent water dispenser product is installed in the home of customers nationwide. For after-sales maintenance, it is easy for the server to save the data and send it back. The remote di ...
Posted on Tue, 07 Jan 2020 07:43:42 -0500 by d00dle
1. Install Oracle 12c
1. Notes for Installing CentOS 7 Operating System
Since this installation of Oracle 12c software is implemented on the CentOS 7 system, install the CentOS 7 operating system first. The installation requirements are as follows:
Firewall configuration options are set to disable;
SELinux is set to disable;
The default ...
Posted on Tue, 07 Jan 2020 04:01:54 -0500 by totof06
Overview of MFS
MooseFS is a fault-tolerant network distributed file system.It distributes data across multiple physical servers and presents users with a unified resource.
1. High reliability (multiple copies of data are stored on different computers)
2. Dynamic capacity expansion can be achieved by attaching a new computer or har ...
Posted on Mon, 06 Jan 2020 18:24:40 -0500 by loopt
Reference blog: linux ElasticSearch.6.2.2 cluster installation and head, Kibana, X-Pack.. plug-in configuration and installation
Reference blog: ELK5.5.1 plug in installation practice summary (head/bigdesk/kopf/cerebo / Chinese word segmentation plug-in)
1. x-pack [default installation of this version]
1 [yun@mini01 ~] $ elasticsearch-plugin ...
Posted on Mon, 06 Jan 2020 17:23:41 -0500 by Mouse
1, Experimental principle
DNAT and SNAT conversion has been done for both incoming and outgoing packets;
Compared with DR, TUN and NAT, only it has the ability of anti attack; (5-component bidirectional hash)
Performance comparison: Dr: > Tun > NAT > fullnat 2, Experimental deployment (1) Experimental environment:
Posted on Mon, 06 Jan 2020 15:02:12 -0500 by moret
In daily operation and maintenance, we will have the phenomenon of daily backup. In this case, it may be required to monitor whether the file exists. The clumsy way is to log in to the server and check whether the file exists in a certain path. In addition, we can use shell or python to write scripts to monitor whether the file exists to reduce ...
Posted on Mon, 06 Jan 2020 12:40:08 -0500 by phppssh
1.1 total size and used size of current physical memory for obtaining operating system information
>>>mem = psutil.virtual_memory()
1.2 obtaining system performance information
>>> import psutil
Posted on Mon, 06 Jan 2020 12:17:16 -0500 by always_confused