Shell

HA (High availability) is highly available and has the following three modes of operation. (1) Master-slave mode (asymmetric mode) Working principle: The host work, the standby machine is in the monitoring preparation condition; When the host is

Loop statements are often used when writing shell scripts. Here a simple summary of the commonly used 3 kinds of circular statements, so that later can quickly reference to write, nonsense do not say, start Demo: 　　1, for Used mainly for:

1, teach you to reduce the external appearance of the notebook wear A good notebook how to maintain their own shell, must be a good packaging, and notebook is the same, you need a good quality notebook outsourcing and a soft notebook bag to protect

Conditional expression ("CONDITIONAL EXPRESSIONS") Conditional expressions are used in [composite commands and built-in command test and [to test file properties for string and arithmetic comparisons.] An expression is constructed using the

The test command expects to find a parameter on the command line that is considered empty when the shell does not assign a value to the variable. This means that when the script is being processed, test will report the error once the script is

I accidentally found a very interesting book of Shell programming, E, content is 101 shell case, stick to tomorrow to read a, write a little experience. The following is an example 001: #!/bin/sh # inpath-verifies That's a specified program

Often in the shell script to block other processes, such as MSMTP mail queue script, this script mutex is not correct, the following is the three found in the file to achieve mutual exclusion of the correct approach. 1. The Flock of Util-linux

Head Command Chinese Introduction: Usage: head [options] ... [File] ... Displays the first 10 lines of each specified file to standard output. if more than one file is specified, the filename is given as the file header before each segment

Monitor hardware Health Shell monitor Cpu,memory,load average, log to log, when load pressure, email notify admin.Principle:1. Get the value of the Cpu,memory,load average2. Determine whether the value exceeds the scope of the customization, for

A start to build the Chinese blog Alliance, both bloggers remind me to do Web site Daquan maintenance of this kind of website is very troublesome, need a lot of energy to debug some of the aborted site, but also to take the blog Encyclopedia of Pine

Environment:Local Host: HA01ETH0:192.168.1.100//External IP address Remote host: HA02ETH0:192.168.1.200//External IP address Local Host HA01 configuration: Copy Code code as follows: [Root@ha01/]# Cd/etc/ssh [Root@ha01 ssh]#

Hadoop, distributed large data storage and computing, free open source! Linux based on the students to install a relatively smooth, write a few configuration files can be started, I rookie, so write a more detailed. For convenience, I use three

One, array, and associative arrays An array is an important part of a shell script that stores separate, independent data as a collection by means of an index. A normal array can only use integers as an array index, and associative arrays not only

In bash, Bash's math is a little awkward, it's hard to adapt and remember, so you have to write a blog post to make it easier to look through. There are four ways to perform mathematical operations: A, let order Copy Code code as follows:

It is customary to use the Linux command line to manage Linux systems, for example: Copy Code code as follows: $ date 211 01:34:58 CST 1999 $ When the user logs in, it actually goes into the shell, and it follows a certain

First, the Shell function All scripts so far in this tutorial have been executed from beginning to end. This is good, but you may have noticed that some of the script segments are duplicated. The shell allows a set of command sets or statements to

Unlike Java, PHP and other languages, the process control of SH is not NULL, such as: Copy Code code as follows: if (Isset ($_get["Q"])) { Search (q); } else { Doing nothing } ?> You can't write this in Sh/bash,

In the morning I wanted to upload some photos to the album, but because all the photos have the extension is jpg rather than lowercase jpg, resulting in "malformed" and can not upload photos. The question now arises: how do you use a shell script to

In the day-to-day operation of the flow of traffic will find the phenomenon of sudden increase or increase in server load and so on, in order to find out why, need to use the Nginx limit module to access IP restrictions, and then can analyze the log.

Linux shell sed awk command (2)-awkawk syntax Format:awk [Options]-F program-file [--] file ...Options:-F FS,--field-separator FSCreate a delimiter with FS as the input line (the default delimiter is a space or tab)-V Var=val,--assign var=valBefore