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1.Posix shared memory concept POSIX stands for Portable Operating System Interface (abbreviated as POSIX). POSIX standard defines the interface standard that the operating system should provide for applications. It is the general name of a series of API standards defined by IEEE for software to run on various UNIX operating systems. Its fo ...

Hadoop cluster construction (continuous update) The relevant resource files that are not used in this paper, the extraction code eeee 1: Preparations to be completed before starting construction Built Linux serverYou can access the public network (ping www.baidu.com), and you can ping itXshell connection (can be omitted)Server version infor ...

Five data types Official website document Redis is an open source (BSD licensed) in memory data structure storage system, which can be used as database, cache and message middleware MQ. It supports many types of data structures, such as strings, hashes, lists, sets, sorted sets and range queries, bitmaps, hyperlogs and geospatial index ...

open/close int fd2; fd2=open(argv[1],O_RDWR | O_CREAT | O_EXCL,0655); if(fd2==-1) { perror("open file error!"); exit(1); } printf("fd2=%d\n",fd2); int ret=close(fd2); printf("fd2=%d\n",fd2); printf("ret=%d\n",ret); Partial code O_RDONLY O_WRONLY O_RDWR: read only write only O_CREAT: create when the f ...

See what types of shell interpreters are available on this machine: [root@sanchuang huahsan]# cat /etc/shells /bin/sh /bin/bash /usr/bin/sh /usr/bin/bash /usr/bin/tmux /bin/tmux sh It's a very old interpreter, more than bash Have a sense of history, No bash Easy to use [root@sc ~]# sh switch to sh interpreter sh-4.4# Switch bash to bash inte ...

linux command: it is essentially a program. Many programs are written in c language, such as python, java, c + +, ruby, php, go, etc [root@localhost ~]# Cat / etc / CentOS release to check the version of linux CentOS Linux release 7.6.1810 (Core) [root@localhost ~]# cali@cali:~$ cat /etc/issue stay Ubuntu Check the version of the system ...

zabbix4.0 deployment zabbix server needs LAMP or LNMP environment, so there are many installation methods here. We choose a relatively simple installation method and install it directly with the source provided by the official. Deployment preparation [root@zabbix-server ~]# uname -a Linux zabbix-server 3.10.0-1062.18.1.el7.x86_64 #1 SMP Tue ...

Virtue wins talent, which is called a gentleman; Talent wins virtue, which is called a villain—— "Zizhi Tongjian · Tang Ji" I Antecedents - reduce duplication of effort Previously, when deploying the running environment of development software in ubuntu, it was necessary to copy and paste the contents in differe ...

Introduction: This paper mainly introduces how to realize the automatic running script of ubuntu 18.04 system startup through systemd. For image download, domain name resolution and time synchronization, please click Alibaba open source mirror station 1, Overview Ubuntu 18.04 does not have / etc / rc.exe by default Local file. It is impos ...

Linux applications usually have three ways to query whether device drivers can be accessed: blocking, non blocking and asynchronous notification. Asynchronous notification: "signal" came into being. The signal is similar to the "interrupt" used in our hardware, but the signal is at the software level. It can be regarded as ...