[Linux] C language Linux system programming creation process, linux
1. process ID
Each process is represented by a unique identifier, namely, the process ID (pid). The system ensures that each pid is unique at a certain time.
1.1 allocate process ID
By default, the kernel limits the maximum process ID to 32768. You can set/proc/sys/kernel/pid_max here. In a short
[Linux] C language Linux system programming-11 TCP communication statuses, linux-tcp
Three-way handshakeThe client initiates a SYN request, and the client is in the SYN_SENT State (the first handshake)After the server receives the message, it changes from LISTEN to SYN_REVD and replies to the client. After the client receives the response, it is in the state of
[Linux] Linux commands for counting folders and files, and linux statistics
# View the number of files in the current directory (excluding files in subdirectories)
Ls-l | grep "^-" | wc-l
# View the number of files in the current directory (including files in sub-Directories) Note: R, representing sub-Directories
Ls-lR | grep "^-" | wc-l
# View the number of
Start to learn linux common commands in detail and stick to one command every day, so this series is a linux command every day. The main reference materials for learning are: 1 "laruence's linux private House dish" 2 http: codingstandardsiteyecomblog7866533linux command 5
Start to learn linux common commands in detail
0. Most commonly used Pstree:[Email protected] temp]# Pstree-a|grep Multe| | '-multepoolser| | '-multepoolser| | ' -2*[{multepoolser}]1. > TopAll system processes can be displayedPress U, and then enter the appropriate execution user name, such as TomYou can see all the processes that Tom user started and the corresponding PID2. > Pstack pidYou can see the running state of each thread under this PID,[[email protected] multepoolserver]# pstack 14944 (PID number of the process)Thread 2 (thread 0x4
[Linux Device Driver] linux address type, linux Device address type
List of address types used in Linux:
User virtual addresses)
The normal address visible to the user space program. The virtual address length is 32-bit or 64-bit. It depends on the underlying hardware architecture. Each process has its own virtual addr
[Linux] linux Command learning-netstat, linux-netstat
Many linux services are related to the network. When the service cannot be called, the startup port is occupied, or the firewall is blocked, you need to query network problems, the netstat command only uses one or two parameters.
Common options:
-A (all) shows
Linux basic Review (1)-Linux System Overview, linux Overview1. What is an operating system? What is the relationship between it and hardware and other software?
An operating system is a system software (or a set of programs) that controls and manages various hardware and software resources in a computer system and effectively organizes multiple programs to run.
Transferred from
Http://beterfly.blogbus.com/logs/23724282.html
Basic commands:Logout: LogoutLog on to login againExit to exit the current user Shutdown: shutdown + timeExample: shutdown now (shutdown now or immediately)Shutdown-C cancel all shutdown settings (shortcut: Ctrl + C)
Restart the computer:Shutdown-r restart timeExample: shutdown-RReboot (immediate restart) is the same as shutdown-R
In Linux, there are seven run_level_number running levels
Tags: share institute public number src inux new VMW http Silicon Valley1.1 Overview 1.2Linux and Windows differences 1.3Centos Chapter 2 installation of VMs and Linux 2.1 VMware InstallationHttp://blog.sina.com.cn/s/blog_c30a9e680102xusf.html2.2 CentOS InstallationHttp://blog.sina.com.cn/s/blog_c30a9e680102xutv.html2.3 Vmtools InstallationHttp://blog.sina.com.cn/s/blog_c30a9e680102xuu3.htmlThis tutorial by the Silicon Valley Institute of Education
Linux services)It is important for Linux users. Disabling unnecessary services can make Linux run more efficiently, but not all Linux services can be disabled. After installing centos Linux today, we found that many services were started when
Linux Log Management Learning1. The log describes the various events that occur on a daily basis. You can use the log to check the cause of the error or the traces of the attack. To facilitate log management, logs are usually stored under/var/log/. Some programs share a log file, while some programs use a single log file. Some large service programs have many log files, a subdirectory is created to store log files. 2. log Type/var/log/secure: System I
* * * * cat/etc/fstab >/dev/null receive incorrect results*/3 * * * * cat/etc/fstab >/dev/null do not receive any resultsNote: Cron environment variables, all commands executed are under the path specified by the PATH environment variable;Path=/bin:/sbin:/usr/bin:/usr/sbinIf the user does not log in, there will be no path, use absolute path/bin/cat or prioritize PATH environment variables[Email protected] ~]# ls/etc/cron.daily/0anacron 0logwatch cups logrot
Lynis is an open-source system security Audit Utility tool that consists of a series of shell scripts that form a comprehensive security-check tool for systems, accounts, processes, and other levels of security risks and are listed in an intuitive way Support the current mainstream Linux platform.First, the Lynis inspection project is generally as followsWhether the system program has been replaced or tampered with to prevent the manager or user from
This feature page summarizes the most popular Linux distributions basic introduction and, if you are a new contact with Linux, the introduction may be helpful to you, if you think Linux use predecessors, you can also leave your comments and experience in the review, so that more people get help!First introduce the following several domestic
"My Linux, I am the Master" My Little story with LinuxAgain late at night without sleep, just see this activity, my thoughts immediately back to the university era, a no longer back to the good times.The first statement is that I am not a great God, at least not at present. It's just one of many Linux learning armies.First knowledge of LinuxThe first time I heard that the word
One, beware the Linux virus
At the beginning of Linux, because of its original excellent design, seems to have innate virus immunity, so many people believe that there will be no virus for Linux to appear, but Linux is finally no exception. In the autumn of 1996, an Australian organization called Vlad in assembly lang
Use rsyslog to audit Linux Users
Rsyslog is part of the standard Linux system. It can write logs in real time and selectively Send Logs to remote log servers.
The dependency on. bash_history or script to audit the commands executed by the user is unreliable. Although both of them record user behavior, they may be tampered with by the user. Rsyslog can be used to write logs to remote log servers in real time
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