第一章、shell脚本基础

[oracle@oracle ~]$ echo $SHELL
/bin/bash
[oracle@oracle ~]$ 

shell课程体系

学习shell脚本的基本流程

shell脚本用在什么地方

[root@oracle ~]# cat /etc/shells
/bin/sh          ---》最小化安装都有
/bin/bash        ---》推荐使用
/sbin/nologin
/bin/dash
/bin/tcsh
/bin/csh
/bin/ksh
[root@oracle ~]# 

env 查看环境变量
set 查看当前用户可以使用的所有的变量

[root@oracle ~]# history
    1  cd /etc
    2  ls
    3  cd sysconfig
    4  ls
    5  cd network-scripts
    6  ls

[root@oracle ~]# !2
ls
anaconda-ks.cfg  Documents  install.log         Music     Public     tmp
Desktop          Downloads  install.log.syslog  Pictures  Templates  Videos
[root@oracle ~]# !cd
cd /backup
[root@oracle backup]# 

[root@oracle ~]# vi /etc/profile
# /etc/profile
# System wide environment and startup programs, for login setup
# Functions and aliases go in /etc/bashrc
HISTSIZE=1000

[root@oracle ~]# alias
alias cp=‘cp -i‘
alias l.=‘ls -d .* --color=auto‘
alias ll=‘ls -l --color=auto‘
alias ls=‘ls --color=auto‘
alias mv=‘mv -i‘
alias rm=‘rm -i‘
alias which=‘alias | /usr/bin/which --tty-only --read-alias --show-dot --show-tilde‘
[root@oracle ~]# 

[root@localhost ~]# vi first.sh
cd /boot/
pwd
ls -lh vml*

[root@localhost ~]# chmod +x first.sh
[root@localhost ~]# ls -l first.sh
-rwxr-xr-x 1 root root 144 04-26 15:02 first.sh

====
声明：以#！开头
注释：以#开头
#!/bin/bash  ---》申明使用bash作为默认shell来执行脚本
#########################################
#Function:    auto fdisk
#Usage:       bash auto_fdisk.sh
#Author:      Customer service department
#Company:     Alibaba Cloud Computing
#Version:     2.0
#########################################
===========

[root@oracle ~]# day=sunday
[root@oracle ~]# echo $day
sunday
[root@oracle ~]# DAY=sun
[root@oracle ~]# echo $day
sunday
[root@oracle ~]# echo $DAY
sun
[root@oracle ~]# 

[root@oracle ~]# name="hai lian tian"
[root@oracle ~]# echo $name
hai lian tian
[root@oracle ~]# 

[root@oracle ~]# DAY=Sunday
[root@oracle ~]# echo "Today is Sunday" >$DAY_file.txt
[root@oracle ~]# ls -a
.txt
[root@oracle tmp]# echo "today is sunday " >${DAY}_file.txt
[root@oracle tmp]# ls -a
.  ..  .esd-0  .ICE-unix  Sunday_file.txt  .X0-lock  .X11-unix
[root@oracle tmp]# 

var2=$(rpm -qf $(which fdisk))
[root@oracle tmp]# var2=$(rpm -qf $(which fdisk))
[root@oracle tmp]# echo $var2
util-linux-ng-2.17.2-12.14.el6.x86_64
[root@oracle tmp]# 

[root@oracle tmp]# name="hello"
[root@oracle tmp]# myname0=‘My name is $name‘
[root@oracle tmp]# myname1="My name is ‘$name‘"
[root@oracle tmp]# myname2=‘My name is "$name"‘
[root@oracle tmp]# myname3="My name is "$name""
[root@oracle tmp]# myname4=‘My name is ‘$name‘‘
[root@oracle tmp]# echo $myname0
My name is $name
[root@oracle tmp]# echo $myname1
My name is ‘hello‘
[root@oracle tmp]# echo $myname2
My name is "$name"
[root@oracle tmp]# echo $myname3
My name is hello
[root@oracle tmp]# echo $myname4
My name is hello
[root@oracle tmp]# 

[root@oracle ~]# echo -e "\tabc123"
	abc123
[root@oracle ~]# echo -e "\tabc\n123"
	abc
123
[root@oracle ~]#

[root@oracle tmp]# cat read.sh
#!/bin/bash
##############################
#Function:	read using
#Us
#Author: 	wangyu
#Company:	haitianjingyu
#Version:	1.0
##############################
read -p "please input you name:" name
read -n3 -s -p "input password:" pwd
echo -e "\n you username is $name ,password is $pwd"
[root@oracle tmp]# bash read.sh
please input you name:hai
input password:
 you username is hai ,password is hai
[root@oracle tmp]# 

#!/bin/bash

read -p "请输入查找的文件夹: " DIR

for i in "$@"

do

if(i!=0){

NUM=$(find $DIR -type f -name "*$i" | wc -l)

echo "以$i结尾的文件的数目是: " $NUM

}

fi

done

read -p "请输入一个挂载点的目录绝对路径：" DIR

mkdir -p $DIR

umount /dev/sr0 &> /dev/null

mount /dev/sr0 $DIR &> /dev/null

(cd /etc/yum.repos.d; tar *.repo *repo.tar  &> /dev/null)

cat << EOF > /etc/yum.repos.d/yumlocal.repo

[Server]

name=Server

baseurl=file:///$DIR

enabled=1

gpgcheck=0

EOF