Shell

Prevent other people from brute force password and deny this IP access to SSH service if someone tries to enter a password error number 5 times.#!/bin/bashlastb | awk  ' {print $3} '  | uniq -c | sort -r  > a.txtsed -ri  ' [email protected]^[[:space:

Here is a summary of some of the recent learning shell knowledge pointsBlog Park-Bang Bang sauce Good * * *1. What is a shell(1) The shell communicates the instructions we enter with kernel so that kernel can control the Jiyu hardware to work

Boss let me put the information in the log summary, good trouble, wrote this script to help work.Need to improve: 1. Crawl log time, only the last time, and this script will catch2. Requires two time difference (e.g. 15:23:34 and 23:23:34), not

Absrtact: In the process of learning, inevitably encounter some commands, the kind of need, but you do not have command. In order to save time, worry about forgetting these, special Open this essay, at any time to record some of the commands used.

DemandThe first two days encountered the need to extract files in a folder of about 10 levels, and then wrote this script.A file structure such as the following: Dir1 ├──a │ ├──b │ │ └──file1 │ └──file2 ├──c │ └──d │

Finding mathematical expressionsVALUE=$[6/3]value=$ ((6/3))Let "value + = 1"Defining local VariablesLocal valuedefining integersDeclare-i valueCommand substitutionValue= ' Command 'value=$ (command)System variables$n, nth parameter$#, number of

For List formFor variable in {list}do statementdonefor var in 1 2 3 4do echo $vardonefor var in {1..4}do echo $vardonefor v Ar in {start.. End.. Step}do statementdonefor i in {1..100..2}do echo $idonefor file in $ (LS) does echo

I want to modify the file name similar to the following batch of files:Aa01_01.txtAa01_02.txtAa01_03.txtAa01_04.txtModified intoBb02_01.txtBb02_02.txtBb02_03.txtBb02_04.txtReplace the head of the file name.============================================

I. Introduction of CrondCrond is a daemon that is used to periodically perform certain tasks or wait for certain events under Linux, similar to Scheduled tasks under Windows, when the operating system is installed, the Service tool is installed by

1. String Qiatouquwei #,%For example:X=aabbaarealwwvvwwecho "${x%w*w}"Aabbaarealwwvvecho "${x%%w*w}"Aabbaarealecho "${x# #a *a}"Lwwvvwwecho "${x#a*a}"BbaarealwwvvwwWhere, # means pinch the head, because on the keyboard # on the left.Where,% is said

IntroductionShell, we often use, with its powerful features, will help us solve a lot of difficult problems. Recently encountered a problem, to run a lot of case, assuming that the serial execution, it takes a long time. Can we get them to go

http://blog.csdn.net/gyanp/article/details/7258356It is often possible to find the following form of command invocation in some scripts, especially when Crontab calls/tmp/test.sh >/tmp/test.log 2>&1The first half of/tmp/test.sh >/tmp/test.log is

1: Errors in redirection and output are directed to the same file in the following way:such as:ls + 1>list.txt 2>&1 or ls + &>list.txtInstead of ls + 2>&1 list.txt2:-exec {} \; This is a command format, not a newline, there is a space in the middle

(1) If statement[Email protected]:/mnt/shared/shellbox/shellif# cat shellif.sh #!/bin/bash# judgment string if ["$" = "Hello"]then echo "\$1= $ "fi# judgment number, if () mode can only be used under bash, not under sh if (>) then echo"

There are two ways that the JDK comes with the runtime.getruntime (). EXEC () and Processbuilder classes, which are introduced after JDK1.5, and are also recommended by the authorities to abandon the use of runtime. Today in the implementation of

When analyzing the process of inserting sorting algorithm performance, it is known that when the array is small or there are more ordered subsequence, the insertion sort will finish sorting the array in a very short time, so you can design a

Replace the tomcat cluster war package with Shell scripts. Run the command to log on to the server without ssh. The configuration file does not change much to overwrite the previous configuration. Profile configuration file Bak =/home/wsm/bakWebapps

The Shell script calls a specified function through passing parameters. When writing some functional scripts, we usually put functions with similar operations or similar parameters in the same shell script, which is convenient to manage, easy to

Shell loop, shellloop1. LoopThe shell loop continues to execute a program until it meets the conditions. There are four types of loops: while LOOP, until loop, for fixed processing, and for numerical processing.2. while LoopThe while loop is

The Shell script calls the specified function by passing parameters. The shell script When writing some functional scripts, we usually put functions with similar operations or similar parameters in the same shell script, which is convenient to