Linux

have been thinking about a problem recently, if hand shake accidentally execute command chmod 777-r/, just no system backup, it is really tragic. The backup of production system is really the most heavy.This session only discusses how to back up

we said the last verse. Apache of the Web service security and optimization. Separately said process optimization, version number of the hidden, session connection time,DNS query. We just have to master these optimization points is enough, we do not

Linux Device Control InterfaceA basic function of a device driver is to manage and control the device while providing the interface for the user application to manage and control the device. The driver supports the device control interface, which is

Chapter One introduction to the Linux kernelThe activity of each processor at any point in time must be summed up in the following three things: Run in user space, execute user process Runs in kernel space, is in the process context,

Three layers of skin (top) of the system callOne, the user state, the kernel state and interruptsThe library function encapsulates the system call.1, what is the user state and the kernel stateIn general, modern CPUs have several different levels of

Zhou Zixuan Original works reproduced please specify the source "Linux kernel Analysis" MOOC course http://mooc.study.163.com/course/USTC-1000029000Use the same system call using the Library function API and the embed assembly code in C code two

Command name: UseraddCommand path:/usr/sbin/useraddExecute permissions: RootSyntax: Useradd user nameFunction Description: Add new userExample: $ useradd YangmiCommand name: passwdCommand path:/USR/BIN/PASSWDExecute Permissions: All UsersSyntax:

Let's start with a simple practice procedure:1#include 2 3 intMain ()4 {5 intC, n =0 ;6 while((c = GetChar ())! ='Q' )7printf"Char%3d is%ccode%d\n", n++, C, c);8 return 0 ;9}This is the program after the compilation of the effect of

Role classification of users under LinuxSuperuser: Has the highest administrative rights to the system and is the root user by default.Ordinary users: Only the files under their own directory access and modification, with the permission to log on

20135130 WangkuandongOne, the user state, the kernel state and the interrupt processing processSeveral different levels of execution of the CPU:High execution level, the code can execute privileged instructions, access to any physical address, the

---restore content starts---1. Append contentAppend the contents of one file to another file:Cat First.txt >> second.txt//append to the end of the Second.txt fileCat first.txt > second.txt//overwrite content in Second.txt file2. View head, tail, etc.

First chapter1. Features of the Unix kernelConcise: Provides only system calls and has a very clear design purposeAbstract: Almost everything is treated as a filePortability: Written in C, making it an amazing porting capability in front of a

1. What is a system callA system call is a bridge between a user program and a hardware device.The user program is used by the system to use the hardware device when needed.The meaning of the system call exists:1) User program through the system to

The following shell is used under CentOS.Get version of a compressed package[Email protected]:/work/lnmp$ ll-a php.tar.gz-rw-rw-r--1 huwei huwei 18355694 March 14:32 php.tar.gz[email protected]:/ work/lnmp$ tar-ztf php.tar.gz|tail-1|awk-f '/' {print

To add user user1 (uid=550 gid=550) as an example:To enter the shell with the administrator root account:#vi/etc/groupAt the end, add by format:USER1:X:550:#wq#vi/etc/passwdAdd at the end:User1:x:550:550::/home/user1:/bin/bash#wq#vi/etc/shadowAdd at

1: Users and GroupsCore elements: allocation of resourcesUser Category:Administrator: ID number 0Normal User: ID numberSystem User: ID number 1-499User ID =uid; Name resolutionGroup Id=gid[[email protected] vp-tools]# IDUid=0 (Root) gid=0 (root)

In one we talked about multitasking where different processes have their own separate code snippets, data segments, and stack segments. Seemingly using this principle can be multi-task isolation, but their starting address of each paragraph is 0,

The first two has already said the multi-task switching principle, left a problem, that is, Linux skipped fragments, the logical address is always equal to the linear address then how to isolate the process?Besides, there are a couple of concepts. 1.

Linux is really good to run, but for development, it is estimated that few people use it.First, installation1. Download tar.gz file2, decompression, you can use the MV command to modify the file name3, establish a soft connection:

Add custom attributes to redmine and add custom attributes to redmine When you use redmine to create a problem, you may find that there is no required attribute. In this case, you can add custom attributes. Take adding the satisfaction attribute