Shell

This is the code development style, in fact, is a function name, equivalent to the underscore division, but read into the package name after the meaning of different. This is defined in accordance with Google's shell development

Original 52779364The problem with script development is that the string splitting operation in the original Java (substring indexof, etc.) does not know what to do (e.g./a/b/c/d.txt I want to know the name of the file)Query information that the

1,$$: Displays the current process ID number[Email protected]:~/linux/shell/how_to_use_var$CatShow_pid.SH #!/bin/BashEcho $$Sleep the[email protected]:~/linux/shell/how_to_use_var$ bash show_pid.SH&[1]9401[email

Export Feature Description: Sets or displays environment variables.syntax:export [-fnp][variable name]=[variable setting value]Additional Note: when executing a program in the shell, the shell provides a set of environment variables. Export can add,

21.1 Why to learn shell programming(1) Linux OPS engineers need to write shell programs for server management when managing server clusters.(2) for Java EE and Python programmers, the need for work, your old assembly requires you to write some shell

#!/bin/bashCase "$" in-a) shiftIf [$#-lt 1]Thenecho Please input parameter: ' "xxx.cn A 192.168.22.22" 'Elseifs=$ ' \t\n 'for param in [email protected]DoA=echo ${param%%‘ ‘*}if testcat /usr/local/etc/unbound/unbound.conf | grep

[TOC]V. Automatic synchronization of files 5.1 configuration scriptsThe core command is to use the Rsync service.[[email protected] sbin]# vim 4.expect#!/usr/bin/expectset passwd "123456"spawn rsync -av [email protected]:/tmp/12.txt /tmp/expect

1. Practice command history, aliases, and special character usages in the shell (4th. 4.2, Section ~4.5)(1) Defining aliasesThe definition of an alias is that it is often enclosed in single quotation marks to prevent the shell from ambiguity about

[TOC]Distribution System-expect What is a distribution system? Now some of the larger enterprises, most of the use of load balancing, and sometimes because some programs to change, or some bug to modify, if only a few servers, it is very

One, Shell special character _cut commandDe-Semantic characters:[[email protected] ~]# c=\ $a \ $b//And #c = ' $a $b ' effect[Email protected] ~]# echo $c$a $bPipe characterCut split[Email protected] ~]# cat/etc/passwd |head-2 |cut-d ":"-F 1//Take

Shell Introduction The shell is a command interpreter that provides interaction between the user and the machine Support for specific grammars, such as logical judgments, loops Each user can have their own specific shell CentOS7

Variable Variables are abstract concepts that can store calculated results or can represent values. Variables can be accessed by variable names. Variable declarationDeclaring variables is generally used in the following

1:hbase start hbase Shell Run command class path contains multiple slf4j Bindings. Error, because the jar package conflicts, so for the jar package with Hadoop, you can delete the other jar package, if you are not sure whether the deletion is

###################### #脚本1: Creating a virtual machine kvm##########################!/bin/bashQcow2_dir=/var/lib/libvirt/imagesRead-p "Please enter the virtual machine number:" Num #主机号If [$num-lt 9];thenNum=0$num # #主机号FiIf [-Z ' $num '];thenecho "

In the previous command Ls/var then in this command LS is the command keyword,/var is the parameter. So how do we do parameter passing when we're making a shell script ourselves?In bash, the first parameter is automatically placed in $ $, the second

Recently a new deployment of the gateway, the user in the implementation of the HBase Shell mode connection HBase, error[[email protected] lib]$ hbase shellslf4j: class path contains  Multiple slf4j bindings.

Whileconditional SentenceGrammar:Condition to meet always doneWhile conditionDoinstructionDone==========Conditional satisfaction exit (rare)Until conditionsDoinstructionDone  Script instance: Daemon monitoringSleep: Print per secondUsleep:

1. string Judgments STR1 = str2 True when two strings have the same content, length Str1! = str2 True when strings str1 and str2 are unequal -N str1 True when the length of a string is

One, parenthesis, parentheses ()1, single parenthesis ()?? ① Command Group. The commands in parentheses will run in a new sub-shell sequence. So the variables in parentheses cannot be used by the rest of the script. Multiple commands in parentheses

Introductory ArticleLinux, we generally use the command line to operate, a good-looking command line, can make our work comfortable, this tutorial can be made to complete the command line style:Of course, you can change the more cool command-line