Shell

When we are testing or commissioning, sometimes you need to generate a file of size, for example, when testing the storage system, you need to reduce the amount of disk space 5G, the easiest way is to copy a 5G file over, but where to get the size

In simple terms, this technique corresponds to the following scenario Suppose there is text as follows Copy Code code as follows: Cccc Aaaa bbbb dddd bbbb Cccc Aaaa Now it needs to be processed, this is simple,

Copy Code code as follows: #! /bin/sh # filename killcpu.sh If [$#!= 1]; Then echo "USAGE: $ " Exit 1; Fi For i in ' seq $ ' Todo Echo-ne " i=0; While True Todo i=i+1; Done "| /bin/sh & pid_array[$i]=$!; Done

First, Introduction Environment variables are typically used to store path lists that are used to search for executables, library files, and so on. For example: $PATH, $LD _library_path, they usually look like this: Copy Code code as follows:

There are many examples of shell script-reading text files on the web, but they don't tell the whole story, only half of it. For example, read a text line from a testfile file in the following format: Copy Code code as follows: $ VI

Test the effect of prefetching, using the CPU to always view the effect. According to the experiment found that the prefetch address in the address before the use of the 10 lines around the code at the effect is better! Copy Code code as

In the shell script, you find a problem with the case statement.This method of specifying lowercase letters [A-z] and uppercase letters [A-z] is no use. The following conditions occur: Copy Code code as follows: [Root@station1 ~]#

First, the common skills Copy Code code as follows: SSH User@server Bash #ssh到远程服务器执行一个脚本, this command avoids uploading scripts to a remote server SSH User@host Cat/path/to/remotefile | Diff/path/to/localfile-

1. Preface In the actual development process, each module will involve some common functions, such as reading and writing files, search, sorting. In order to reduce the redundancy of the Code and improve the quality of the code, these common parts

The last time we sent a Python update Google hosts script, today saw someone sent a shell to get Google hosts script, I took to a slightly more simple processing, the following gives you the shell version of the update of Google hosts script.

The company server has been dying for the last two days because of the full memory usage. Really can't stand the old call room to help people to restart, specifically wrote a script to release the memory, of course, this server is not too important,

What I want to say here is the parentheses in several shells, the braces and the bracketed variables, and the use of the command, as follows: 1.${var}2.$ (CMD)3. () and {}4.${var:-string},${var:+string},${var:=string},${var:?string}5.$ ((exp))6.$

A few days ago wrote seven bull demo, with Bash wrote a convenient installation of the script, involving the path-related judgments, from StackOverflow, plus their own practice to tidy up. Simple version The following is one of the simplest

awk regular Expressions and built-in function examples are detailed: 1, Fuzzy matching: Copy Code code as follows: awk ' {if ($3~/97/) print $} ' DATA.F: Print the line if "97" is included in the third item awk ' {if ($4!~/ufcx/)

Copy Code code as follows: #!/bin/bash While ["1"] Todo Eth=$1 rxpre=$ (Cat/proc/net/dev | grep $eth | tr: "" | awk ' {print $} ') txpre=$ (Cat/proc/net/dev | grep $eth | tr: "" | awk ' {print $} ') Sleep 1 rxnext=$ (Cat/proc/net/dev |

Today, my company colleagues to my entire ADSL automatic redial shell, and detect whether connected to, so as to ensure that the internal test server does not drop the net, OK, I sent the script below. System: CentOS 5.x Script 1: Copy Code

Because the local area network host many, the VLAN also many, for often can know the number of on-line host, writes the script to examine the on-line host. The effect is: the host online display green, the host offline display red results. Usage:./

1. Background When multiple processes may perform operations on the same data, these processes need to ensure that the other processes are not operating to prevent damage to the data. Typically, such a process uses a "lock file", which means that

Ord functions are not provided directly in awk, so when you convert a character to a code, you need to implement it yourself Copy Code code as follows: awk ' begin{for (i = 0; i This mainly constructs the data structure of

First, simple version Refer to the example of StackOverflow and change one out: Copy Code code as follows: While ifs= ' = ' Read var val Todo if [[$var = = \[*]]] Then section=$ (echo $var | sed ' s/^\[\ (. *\) \]$/\1/')