Introduction to Linux shell and expect dead

1.1 Shell some small summary

1, 0 wide assertion 2, Print menu 3, getopts option Introduction 4, script query IP geolocation

1.1.1 grep zero-width Assertions (0 wide assertion)

It means taking out what you want and getting rid of things you don't care about.

-O: Indicates exact match-P: Indicates a regular expression using Pcre to match

1. Antecedent assertion: Represents the position preceding the match expression

[Email protected] ~]# echo "Cooking Sing" | Grep-op ' [a-z]* (? =ing) ' Cooks

The above example: (? =ing) This is the assertion, meaning that when the assertion exists, the judgment match, match to the

The object is the string in front of it. Of course, the preceding string you also need to match the regular expression, for example: ([A-z]) *, because

The regular is greedy, so the assertion will always end up from the right side to the mismatched one.

2. Post assertion: Indicates the position following the match expression

[Email protected] ~]# echo "ABCDEFG ABCA" | Grep-op ' (? <=abc). * ' DEFG ABCA

The above example: (? <=abc) is the assertion, as opposed to above, it is to start from the left side of the match

Small combat

(1) Take IP address

[[email protected] learn]# ifconfig eth0      link  encap:ethernet  hwaddr 06:66:91:e7:9a:74             inet addr:10.10.11.15  Bcast:10.10.11.255  Mask:255.255.255.0           UP BROADCAST RUNNING MULTICAST   mtu:1500  metric:1          rx packets :1234086 errors:0 dropped:0 overruns:0 frame:0           TX packets:829131 errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:1000            RX bytes:1182619038  (1.1 gib)   tx  bytes:88948632  (84.8  MiB)           Interrupt:246 lo         Link encap:Local Loopback             inet addr:127.0.0.1  Mask:255.0.0.0           UP LOOPBACK RUNNING  MTU:16436  Metric:1           RX packets:62861848 errors:0 dropped:0  overruns:0 frame:0          tx packets:62861848  errors:0 dropped:0 overruns:0 carrier:0           collisions:0 txqueuelen:0           rx  bytes:10133085846  (9.4 gib)   TX bytes:10133085846  (9.4 gib)

Remove the IP address of the EM1

[Email protected] ~]# Ifconfig | Grep-e ' (eth0|em1) '-A 1|grep-op ' (? <=ADDR:) [\d.] + ' 10.10.10.180

(2) Time to take the log

If the Nginx backup log format file is Access_20150408_nginx.log

[Email protected] ~]# echo "Access_20150408_nginx.log" | Grep-op ' (? <=access_). * (? =_nginx) ' 20150408

1.1.2 Print Menu

echo command

-N: Do not wrap-e: Turn on the backslash ESC escape. If the following character appears in the string, it is handled in particular, not as a general text output

\a a warning sound; \b Delete the previous character; \c ends with a newline symbol, \f wraps but the cursor remains in its original position; \ n Wraps and the cursor moves to the beginning of the line; \ r The cursor moves to the beginning of the line, but does not wrap; \ t inserts tab; \v is the same as \f; \ \ insert \ character; \nnn inserts ASCII characters represented by NNN (octal)

Read command

-P: Interactive display prompt information-T: Timeout time-N: Set number of characters-s: not visible (useful when entering a password)-D: Delimiter

Implement a simple menu

#!/bin/bashmydate= ' date +%d/%m/%y ' this_host= ' hostname ' user= ' whoami ' while true;do  # clearcat <<eof        _____________________________________ _______________                 User:  $USER  Host:  $THIS _host date:  $MYDATE           ____________________________________________________                 1: list files                  2: See memory  Total                 3:  See who is on the systeme                  4: help screen                  q: exit menu         ____ ________________________________________________eofecho -e  -n  "\t You Choice[ 1,2,3,4,q]>  "read choiceecho  $CHOICEcase   $CHOICE   in 1)  ls ;; &NBSP;2)  free -m ;; &NBSP;&NBSP;3)  who ;;  4)  echo  "This is help screen , nothing here yet to  help you ! "  ;; Q|Q)  exit 0 ;; *)  echo -e  "\t \007 unknown user reponse"  ;; esac  #echo  -e -n  "\t hit the return key to continue "  read -p  "  Hit the return key to continue "   Godone

1.1.3 Getopts Introduction

Different hints or different executions depending on the parameters

Let's look at a column first.

#!/bin/bash while getopts  "H:n:a"  argdo         case  $arg  in                  H)                          echo  "Welcome to beijing arg: $OPTARG ";;                 n)                            echo  "your name is  $OPTARG";;                 a)                           echo  "your age is  $OPTARG " ;;                 :)                            echo  "The -h arg must have one args";;                 ?)                           echo  "Please input your select args"  ;;         esac done

Execution results

[[Email protected] learn]# sh get.sh-h "Hello World"-n budongshu-a Welcome to Beijing Arg:hello worldyour name is BU Dongshuyour Age is

How to use getopts scripts

Script. SH option_string variable

The first parameter uses the-H option. The second parameter is the Hello World string followed by-H

Parse the above example

Define options:

You can see the phrase "h:n:a" arg in the while getopts, so the definition of the option "H:N:A" is defined here.

Colon meaning

1, the letter followed by a colon to indicate that this option must have parameters, i.e.-H and-n must provide a parameter,

The value of the parameter is stored in the variable $optarg

2, there is no colon after the letter for this option can not follow the parameters, follow up and do not assign value. You can see that-a has no value

3, a colon at the top of the letter indicates that the error message is provided by ignoring the command itself. Here's a demonstration

Script

#!/bin/bash while getopts  "H:n:a"  argdo         case  $arg  in                  H)                          echo  "Welcome to beijing arg: $OPTARG ";;                 n)                            echo  "your name is  $OPTARG";;                 a)                           echo  "your age is  $OPTARG " ;;                       ?)                           echo  "Please input your select args"  ;;         esac done

Execution result: The command internally provided an error in the middle of the

[[Email protected] learn]# sh get.sh-h hello-n Welcome to Beijing arg:helloget.sh:option requires an argument--Nplea Se input your Select args

Plus a colon to see later

Script

#!/bin/bash while getopts  ": H:n:a"  argdo         case  $arg  in                  H)                          echo  "Welcome to beijing arg: $OPTARG ";;                 n)                            echo  "your name is  $OPTARG";;                 a)                           echo  "Your age is  $OPTARG " ;;                       ?)                           echo  "Please input your select args"  ;;         esac done

Execution result: You can see a missing error.

[[Email protected] learn]# sh get.sh-h hello-n Welcome to Beijing arg:helloplease input your select args

Error message prompt

Script

#!/bin/bash while getopts  ": H:n:a"  argdo         case  $arg  in                 H)                          echo  "Welcome to beijing arg: $OPTARG";;                 n)                           echo  "your name is  $OPTARG";;                 a)                           echo  "Your age is  $OPTARG " ;;                 :)                            echo  "The -h arg must have one args";;                 ?)                          echo  "Please input your select args"  ;;         esacdone

: Colon in case, when you ignore the system command error (that is, add: number), there is a parameter-H followed by a colon, the representative must follow an option parameter, if not followed by the option parameter, it will prompt for your custom error message,-A is not required to provide parameter options ( Because there is no colon appended to the letter, the script is executed without a parameter (or when the-a option is not followed), and no error is given.

? Case question mark, when the following parameters such as-e does not exist when the error

All of the above error $optarg variables are not available

1.1.4 Script Query IP geolocation

Script

#!/bin/bashgetip=$ (curl-s ip.cn?ip=$1) iparea=$ (Echo $Getip |awk-f ":" ' {print $} ' |awk ' {print $} ') ipisp=$ (Echo $Getip |awk-f ":" ' {print $} ' |awk ' {print $} ') if [!] $];thenip=$ (echo $Getip |awk-f ": ' {print $} ' |awk ' {print $} ') echo $ IP $IParea $IPispelseecho $IParea $IPISPFI

Execution results

[[email protected] script]#./getip.sh (current extranet IP address) 117 ... Beijing.... [Email protected] script]#/getip.sh 8.8.8.88.8.8.8 US google[[email protected] script]#./getip.sh 114.114.114.114114.114.114.114 Jiangsu province Nanjing Wind Network

2.0 Expect Introduction

Installation

Yum Install Expect-y

Script

#!/usr/bin/expect-f set IP [lindex $argv 0] Set password "111111" spawn ssh [email protected] $ipset timeout expect { "Yes/no" {send "yes\r"; exp_continue} "password:" {send "$password \ r"}}expect "]#" send "free-m\r" int Eract#expect EOF #exit

Execution results

[[email protected] learn]# hostname bj-idc-15[[email protected] learn]# ./ Test1.exp 10.10.10.14 spawn ssh [email protected][email protected] ' s  password: last login: mon apr 11 16:24:49 2016 from 10.10.11.15[[ email protected] ~]# free -m              total       used        free     shared    buffers      cachedmem:          7870        2782       5088           0        341       2219-/+  buffers/cache:        220       7650swap:          3999         57        3942[[email protected] ~]# hostname bs01

This article is from the "Hu San DAO" blog, please be sure to keep this source http://bdstravel.blog.51cto.com/8870307/1762647

Introduction to Linux shell and expect dead