Shell

$# is the number of arguments passed to the script. The name of the script itself is the first parameter passed to the shell script , and the second argument is passed to the shell script [email protect Ed] is a list of all parameters passed to the

Typically, we enter commands from the command line each time to get a response from the system. This is obviously inefficient when we need to enter commands one after the other and finally get the results. To achieve this, we usually use shell

Break, continue, exit, return are generally used to control the direction of the loopStart with a script descriptionFor ((i=1;iDoIf [$i-eq 3]Then# break# continue# exitFiEcho $iDoneEcho OKResults of the outputResult of break12OkResults of continue124

First, Judge read the string value An expression meaning ${var} Variable var with the same value as $var ${var-default} If

Article Source: (Linux Shell) The first chapter--Small trial sledgehammer (next)1.6 Arrays and associative arrays1.6.1 Preparation KnowledgeBash supports both normal and associative arrays, and normal arrays can use integers only as an array index,

Source: (Linux Shell) Chapter One--Small trial sledgehammer (i.)Starting today, let's study the book "Linux Shell Scripting Raiders".1.1 IntroductionA shell script is usually a text file that starts with #!, as follows:#!/bin/bashThere are two ways

The second of Shell programming learningFirst, Bash's condition testTest method, or test writing:Test EXPR[EXPR][[EXPR]]For example: Test whether the variable user_name is rootTest $User _name= "root"[$User _name = = "Root"][[$User _name = =

Shell script error: "[: =: unary operator expected"Md5_109a = "81ab961153b62d207f0f517048881b5d"Md5_1_ B = 'md5sum install. Bin | awk '{print $1 }''If [$ md5_109a! = $ Md5_1_ B]Cause: when the file install. Bin does not exist, $ md5_1_ B is empty so

#! /Bin/bash# Initializing Environment VariablesSource. bash_profile# Inherent date format in log nameF_name = 'date + % Y % m % d'# Log path and nameLOG_FILE =/backup/DB/RMAN/log/RMAN $ f_name-0401.logEcho $ LOG_FILE# Counting the number of log

Recently, some tests were conducted in Erlang shell. In order to make the test result data more intuitive, we wanted to align the data to be printed and achieve the same effect as imaging tables. The idea was to insert a tab in the data. Of course,

#!/bin/bash## Judging the element is a file or a folderif [ $# -lt 1 ];then  echo "ERROE!! Usage: ckfile.sh ARGS1 [ARGS2...]"  exit 4fifor i in `seq 1 $#`doif [ -f $1 ];then  echo $1 is a commom fileelif [ -d $1 ];then  echo $1 is a directoryelse  ec

This article is based on the "Unix/Linux Programming Practice tutorial". This is a book that explains programming for Unix systems. It focuses on practice and is difficult to understand. We recommend that you read this article, there will be a

The columns in the text line are broken: Awk 'in in {srand ()} {for (I = 1; I   The lines in the text line are broken down: Awk 'in in {srand ()} {B [rand () Nr] = $0} end {for (X in B) print B [x]} 'Data Shuf-n1000 data   Use a.txtas the patternto

Bbb board Lesson 5: shell script programming Experiment In Class 1, we test and control the high/low output of the gpio port through simple echo commands to enable and disable the control of an LED indicator. This section uses shell script

[From] http://blog.chinaunix.net/uid-168249-id-2860686.html Reference: 1. system environment variables after a user logs on to the system:$ Home user's own directory$ Path: the directory to be searched during Command Execution$ TZ Time Zone$

1 shell variable BasicsShell variables are very "weak" variables. By default, a variable stores a string, and shell does not care about the meaning of the string. Therefore, to perform mathematical operations, you must use commands such as let,

1. first introduce the usage of Alias (alias) Alias LA = 'LS-a' alias B = 'CD... 'and so on Alias is a good thing. It can save a lot of time when using shell. 2. But one day I found that the if statement cannot be used when executing the shell

Shell Command sshpass non-interactive SSH password verification Shell Command sshpass non-interactive SSH password verification # Install sshpasssshpass : Http://sourceforge.net/projects/sshpass/ Download it as a tar.gz compressed package. $

Shell Command sshpass non-interactive SSH password verification, sshpassssh Shell Command sshpass non-interactive SSH password verification # Install sshpasssshpass : Http://sourceforge.net/projects/sshpass/ Download it as a tar.gz compressed

An example of a Shell with parameters and a shell parameter #! /Bin/bash # Program: # LZSH server log filter # History: #2014/07/01 Kom First release #2014/07/03 Kom Remote and multi-param support # Set PATHPATH =/bin:/sbin: