Linux environment programming shared memory Area (ii): POSIX shared memory area

The concept of shared memory areas is now extended to include memory areas that are shared between unrelated processes. POSIX provides two ways to share memory areas between unrelated processes :1. Memory mapped file: Opened by the Open function,

Linux operation Tip: "Can ' t open file for writing" or "Operation not permitted" workaround

The use of the VI command on Linux to modify a file content, found unable to save, each time after the use of ": q!" command can exit normally but use ": wq!" command to save the file and exit when the message appears:E212:can ' t open file for

Linux CPU performance Indicators and explanations

CPU utilization-cpuusage RateCPU Utilizationis the most intuitive indicator of how a program occupies system resources, i.e.CPUusage rate. IfCPU Utilizationin the5%-10%there is basically no impact on the system, you can not pay attention. But if the8

<linux system hostname Command detailed >

Hostname small knowledge of the use of commandsWe all know that the hostname command is to view the host name and modify the hostname.[[email protected] ~]# hostname //view host name of[[email protected] ~]# hostname redhat /

Linux tips: Use screen to manage your remote sessions

Transfer from you often need SSH or telent telnet to a Linux server? Do you often have headaches for long-running tasks such as system backups, FTP transfers, and so on. Usually we open a

Linux Kernel Learning-process

Say a few terms first:First, five segments of the Linux processLet's briefly summarize what 5 different data areas are included in the memory space of the process.Focus:Code snippets, data segments, stack segments, this is a conceptHeap, stack,

"Linux" Linux basic command literacy

"VI Use"1. In command line mode: Place the cursor on the function in the VI editor.SHIFT + KCan direct man manual, Exit man manual direct press two times Q: Directgg=gCan make files automatically aligned:GGNavigates to the beginning of the file, G

Linux/unix method of assigning process ID and source code implementation

In the Linux/unix system, each process has a unique process ID represented by a nonnegative integer. Although it is unique, the ID of the process can be reused. When a process terminates, its process ID can be used again. Most Linux/unix systems use

Linux Environment Programming Synchronization (IV): POSIX semaphore

Semaphores are primitives used to provide synchronization between different threads of different processes or a given process. There are three types: POSIX-known semaphores , using POSIX IPC name identifiers,POSIX memory-based semaphores , stored in

Dynamic Connection Library under Linux and its implementation mechanism

Linux is similar to the dynamic Connection library concept for Windows, but the implementation mechanism is different. It introduces the concept of the Got table and the PLT table, uses various relocation items synthetically, realizes the "floating

Linux modification Time-[command action]

We generally use the "date-s" command to modify the system time. For example, the command to set the system time to June 10, 1996 is as follows.#date-S 06/10/96The command to set the system time to 1:12 P.M. 0 seconds is as follows.#date-S

Linux find more than one specified type file at a time, specify a file or exclude a class of files, match multiple key in GREP

Http:// find a method that matches multiple keywords in GREP at a time by finding multiple specified files or excluding certain types of files(1) Linux find more than one specified file at a

Linux command Help

Linux command format:command [options] [arguments]Command: CommandsOptions: Parameters[] the expression is optional;<> the expression is changeable;X|y|z that only one can be selected;-ABC represents a mixed use of three parameters (or any

Linux socket programming with TCP example

1, how to communicate between processes in the network?The local interprocess communication (IPC) is available in a number of ways, but can be summarized in the following 4 categories:Message delivery (pipeline, FIFO, Message Queuing)Synchronization

Linux system calls, buffered Io, unbuffered IO

1. What is a system call?The Linux kernel sets up a set of subroutines that are used to implement various system functions, called system calls.  Linux system calls are provided as part of the C library, and users can invoke them in their own

Linux Terminal Multi-window tool Tmux compilation and installation

Tmux (full name is Terminal multiplexer) is an excellent end-use software, similar to GNU screen, but from OpenBSD, with BSD licensing. The most intuitive benefit of using it is that when you log in to a remote host through a terminal and run Tmux,

SVN client RabbitVCS-2 in Linux

As we all know, since SVN's debut, many people have predicted that CVS will be replaced by it. Just as they predicted that Maven would replace Ant. Visible, SVN's popularity. In Windows, the most commonly used open source free SVN client is

Linux Process Control--exec function family

Original: Introductionin Linux, there is no exec () function, and exec refers to a set of functions, a total of 6, respectively:#include extern char **environ;int execl (const char

Differences between Windows and Linux line-tailed characters (EndOfLine)

The line endings of text files differ from one operating system to another.1. The provisions of each system regarding the line-tailed character (End-of-line)Unix ends with ' \ n ' at the end of each line, and the Windows system ends with "\ r \ n"

Supports multiple operating systems and multi-locale settings, including Windows, MAC, Linux and Unix

Universal Barcode Font Advantage multiple barcode types that can be generated in a single font compatible with multiple operating systems and languages with double-byte character sets, for example, Japanese, Chinese, and KoreanSpecific features:

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