Linux

B useful Linux commands• Man {command}: This opens the Help file for the specified command. For example, type manPWD.• PWD: Print working directory.• Ls: list files.• CD: Change directory.• Mkdir: Create a new directory.• CP: copy a file.• CP-R:

Long Double uses % lf // in Linux, note that it occupies 12 bytes. In Windows, use % F directly. % D: returns a signed integer in decimal format.% U: returns an unsigned integer in decimal format. % X, % x: returns an unsigned integer in

Start and Stop services at oracle9i in linux       # Service stop ProcessSQL code Su-oracle Sqlplus/nolog Conn/Sysdba Shutdown immediate su - oraclesqlplus /nologconn /as sysdbashutdown immediate   # Start the Service ProcessSQL code

I. Memory CacheThe kernel uses the kmalloc and kfree functions to allocate and release a memory block, which is similar to the malloc and free functions in the libc library of the user space, however, kmalloc has different allocation marks to

Kernel options during boot Linux users pass the Kernel configuration options to the Boot Record, The Boot Record, and then the options to the kernel, and then fine-tune the kernel through the boot configuration parameters. During system boot,

Clone and copy of the buffer zoneWhen a buffer needs to be specially processed, you may need to modify the content of the sk_buff descriptor, but the kernel does not need to completely copy the sk_buff structure and the associated data buffer. To

Virtual Device Virtual Devices are abstracted based on one or more real devices. The correspondence between virtual devices and real devices can be one-to-one, one-to-many, and multiple-to-one, virtual devices may be created on top of other virtual

[Tom @ Agilysys: etc] $ vi/etc/sudoers # # Adding HOME to env_keep may enable a user to run unrestricted# Commands via sudo.## Defaults env_keep + = "HOME" Defaults secure_path =/sbin:/bin:/usr/sbin:/usr/bin # Next comes the main part: which users

Let's first write a simple script and then explain the meaning of each variable.# Touch variable # vi variable script content :#! /Bin/shecho "number: $ #" Echo "scname: $0" Echo "First: $1" Echo "Second: $2" Echo "argume: $ @" Echo "show parm

File system is a basic knowledge of linux and a necessary knowledge of linux. This article will take a high-level view to understand the linux File System, this section describes linux disk partitions and directories, basic mounting principles, file

Linux socketResearch on Binding Mechanism      1. Overview: In a multi-link environment, it is difficult to ensure that data is transmitted on the correct link. This article mainly analyzes the implementation of the Linux socket binding

Document directory 2.2 Data Structure Relationship:   5.3 an actual case Linux network system learning: Neighboring Subsystem1. Overview The next step is to obtain the L2 address corresponding to the L3 address. This process is called neighbor

Linux comes with a watchdog implementation for monitoring system running, including a kernel watchdog module and a user space watchdog Program Kernel watchdog module: The kernel watchdog module communicates with the user space through

1. SYS-V Method You can use the IPCS command to view SYS-V-related IPC usage 2. POSIX Method 1). Message Queue Linux provides the mqueue file system type, which can be used to observe the usage of POSIX message queues. $ Mkdir/dev/mqueue $

% Ftp host name/IP/* log on to the ftp server and enter the user name and password */ Anonymous Logon: username input: anonymous Password Input: any string in the email format FTP> ascii: Set File Transfer in ASCII mode (default)FTP> bell: an alarm

The incorrect impressions and understandings are listed as follows: 1. There are too few software in linux. A: There are a lot of software in linux. When windows is still in the mother's stomach, Unix has become very popular. Do you know what is the

This article briefly introduces how to add a system call for linux. That is, add an api function for linux. Through this article, we should learn how to modify the linux source code and compile the kernel. First: 1: cd/usr/src/linux/kernel 2: vi sys.

Interview Questions are a set of PEN questions, which are more classic (closed exam, 100 minutes to finish the exam, it is best to write the steps to solve the problem). If you can correct 7%, it means that you step into the door of linux

I. Some General C questions Question 1: Write the following program results: Int m [] [3] = {, 9 }; Int I, j, k = 2; For (I = 0; I Printf ("% d", m [k] [I]); } Question: The dual array is displayed at a glance! Question 2: Which of the following

User Management: Sudo passwd root: Set the root password Su root: Enter the root user File and folder operations: Touch filename: create a file Rm-rf/a/B/c: remove non-empty directories Tar-xjvf filename.tar.bz2: Decompress the .tar.bz2