(ext.) Linux Expr command parameters and usage explanations

Linux expr command parameters and usage detailsOriginal: http://blog.csdn.net/tianmohust/article/details/7628694Expr usageThe expr command is generally used for integer values, but can also be used for strings. The General format is:#expr argument

Linux in tar. GZ bz2 XZ How to use decompression

tar.gz/xz/bz2 How to DecompressTar usage: Tar was originally used to package on tape drives, and now tar can package any file, package multiple files and directories into a single file, and also support xz/bzip2/gzip compression, separate tar does

View hardware information under Linux (MAC,IP address, HDD model, serial number, etc.)

First, check the network card MAC address#安装lshw[email protected] ~]# Yum install LSHW#使用方法[[email protected] ~]# lshw-c network *-network:0 description:ethernet Interface Produc T:netxtreme II BCM5709 Gigabit Ethernet vendor:broadcom Limited

LINUX Directory file Operations

01: Create directory = = mkdir/directory Name02: Recursive Create directory = = mkdir-p/directory Name03: Switch directory = cd directory path04: Show current directory: PWD05: Superior and current directory = CD. and CDs.06: Delete Empty directory =

Customized RPM packages for Linux systems

FPM Packaging ToolsFPM's author is Jordansissel.FPM's GITHUB:HTTPS://GITHUB.COM/JORDANSISSEL/FPMThe FPM function is simply to convert one type of package into another type.1. Supported source-type packagesDir packages the directory into the

Linux system resolved Getch () input value does not show back

Under the Linux system development C program will encounter the system does not support Conio.h header file, cannot use Getch () do not echo function. The following shows how to construct a function to implement numeric input without

Monitoring and log analysis of high CPU in Linux system

When using a Linux system, consume CPU resources too high and use scripting to troubleshoot:1, real-time monitoring, once there is a high CPU consumption process, the program starts;2, then the process analysis, to draw the corresponding thread;3,

Under Linux, how to execute the ifconfig command with regular expressions, only extract the IP address!

The method is too many, first simple to concise and gradual.1.[Email protected] ~]# ifconfig eth0|grep ' inet addr: ' # # #过滤不是IP地址的行inet addr:192.168.16.100 bcast:192.168.16.255 mask:255.255.255.0Or[Email protected] ~]# ifconfig eth0|sed-n ' 2p ' #

After Linux acquires time--Custom time format

Custom Time FormatWe can usestrftime() function to format the time as we want. Its prototype is as follows:size_tstrftime( Char *strdest, size_t MaxSize, const Char *format, Const struct TM *timeptr);We can place the time information stored in the

Linux basic Commands (i)

GoalBe familiar with the commands commonly used by LinuxLsClearCdPwdMkdirTouchRmCpMvTreechmodFindGrepredirectSoft connections, hard linksCompressionShutdownRebootW.H.O.ExitpasswdSudo1> viewing file information: lsLS is the abbreviation of the

Modified date and time of Linux learning commands

Modified date and time of Linux learning commandsI. Date and time modification1. View time and date[[email protected] ~]# dateFriday, November 03, 2017 11:39:49 CSTOr[Email protected] ~]# clockNovember 03, 2017 Friday 11:42 52 sec -1.563496

How to view all running processes (PS) in Linux

You can use the PS command. It can display information about the current running process, including the PID of the process. Both Linux and UNIX support the PS command, which displays information about all running processes. The PS command can

Linux basic commands

shell--command InterpreterThere are several different types of shells in the Linux environment, where the bash shell is the default installed and used shellClear the terminal screen: Clear, Ctrl+l and CLS (if first input: alias Cls=clear) effect is

Linux Multi-host SSH trust operation---noob ....

After creating the virtual machine--Ssh-keygen generating public and private key pairs-RW-------1 root root 1679 November 4 09:18 Id_rsa-rw-r--r--1 root root 395 November 4 09:18 id_rsa.pubId_rsa inside is the private key information needs to be

Linux Administrator technology -01-selinux, configuring advanced connections, Firewall management policies,

security-enhanced Linux (SElinux)– United States NSA National Security Agency-led development, a set of mandatory access control systems to enhance Linux system securityPurpose: Mandatory access control system– integrated into the Linux kernel (2.6

Linux limit root telnet, su command, sudo command

SU command:1, SU Switch user command example: su-aming2. WhoAmI View Current User commands3. PWD View current directoryExample: Input su aming can also switch users, but the directory is not in its own user directory, as follows:[email protected] ~]#

Introduction to special permissions for files on Linux systems

1. special File Permissions Example[Email protected] test]# ls-ld/bin/passwd/tmp/-RWsr-xr-x. 1 root root 27832 June 2014/bin/passwdDRWXRWXRWT. Root root 247 Oct 22:17/tmp/2, special permission Introduction: SUID, SGID, STICKYSecurity context:The

SSH login without password: Only two simple steps (Linux)

Last updated April 8, 2017Category latest Articles server Security label RSA SSH Key Asymmetric Encryption If you manage a Linux server, you will know how cumbersome it is to enter a password every time you ssh in or use SCP to copy files. This

The difference and format of ps-ef and PS aux under Linux

Linux Displays the system process command PS, the most commonly used are ps-ef and PS aux. What is the difference between the two? There is not much difference between the two, to discuss this issue, to go back to the UNIX system in the style, the

Linux Cloud Foundation System Installation

Dear friends, after a day of time, Xiao Xiao came again.Last time we talked about the history of Linux, let's talk about the installation of Linux systems today.Because Xiao Xiao's computer monitor is 4K, there is no way to find the normal display,

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