sed Demo

#!/bin/bash
#File: sedDemo.sh
#Author: lxw
#Time: 2014-08-18
#Usage: Demonstration for sed.

#NOTE: use " instead of ‘ in sed.
echo "Demo -----------------------"
sed "s/Chen Hao‘s/my/g" pets.txt

echo "-i选项: 修改文件本身-----------------------"
sed -i "s/my/Chen Hao‘s/g" pets.txt

echo "\<fish:以fish开头 -------------------------"
sed "s/\<fish/FISH/g" pets.txt
echo "sh\>:以sh结尾-------------------------"
sed "s/sh\>/SH/g" pets.txt

echo "s匹配替换-----------------"
echo "第3行-------------------"
sed "3s/Chen/CHEN/g" pets.txt
echo "3-6行(既包括第3行，又包括第6行）-------------------"
sed "3,6s/Chen/CHEN/g" pets.txt
echo "i -> I: 每行的第一个i-------------------"
sed "s/i/I/1" pets.txt
echo "i -> I: 每行的第2个i(包括第2个i）以后的i --> 不是第2个字母-------------------"
sed "s/i/I/2g" pets.txt

echo "多个s匹配-----------------"
sed "1,3s/Chen/CHEN/g; 5,10s/This/That/g" pets.txt
echo "上面的命令等价于这条命令--------------------"
sed -e "1,3s/Chen/CHEN/g" -e "5,10s/This/That/g" pets.txt
#sed -e "1,3s/Chen/CHEN/g" -e "5,$s/This/That/g" pets.txt    #$字符的使用有点儿问题

echo "&字符的使用-------------------"
sed "s/Chen/[&]/g" pets.txt

#圆括号括起来的正则表达式所匹配的字符串可以当成变量来使用，sed中使用的是\1,\2
echo "sed的格式化文本处理-----------"
sed "s/This is my \([^,]*\),.*is \(.*\)/---\1:\2---/g" my.txt

echo "N命令: 只匹配奇数行---------------------------"
sed "N;s/my/your/" my.txt
echo "每两行和并为一行(例如：第一行和第二行合并，但第二行和第三行不合并)----"
sed "N;s/\n//" pets.txt

#a命令和i命令
echo "第一行前面添加一行-----------------"
sed "1 i This is my monkey, my monkey‘s name is wukong" my.txt
echo "最后一行后面添加一行-----------------"
sed "$ a This is my monkey, my monkey‘s name is wukong" my.txt
echo "在匹配到/my/的行后面添加一行-----------------"
sed "/my/a This is my monkey, my monkey‘s name is wukong" my.txt    #只要这一行中有匹配的字符串就会添加

echo "c命令: 整行替换,替换匹配行-----------------"
echo "替换第1行-----------------"
sed "1 c This is my monkey, my monkey‘s name is wukong" my.txt
echo "匹配到/fish/的行-----------------"
sed "/fish/c This is my monkey, my monkey‘s name is wukong" my.txt

echo "d命令: 删除匹配行-----------------"
sed "1d" my.txt
echo "删除匹配到/fish/的行-----------------"
sed "/fish/d" my.txt
#sed "2,$d" my.txt    #$字符的使用有点儿问题

echo "p命令: 打印匹配行----------------------"
echo "匹配fish并输出，fish行被输出了两遍，因为sed处理时会把处理的信息输出----"
sed "/fish/p" my.txt
echo "-n选项: 只输出匹配行------------------------"
sed -n "/fish/p" my.txt
echo "从cat到fish的行,而不仅仅是cat和fish行------------------------"
sed -n "/cat/,/fish/p" my.txt
echo "从第一行打印到匹配fish的行-------------------"
sed -n "1,/fish/p" my.txt
echo "+3表示后面连续3行------------------"
sed "/dog‘s/,+3s/^/# /g" pets.txt

echo "对3行到第6行，执行命令/This/d---------"
sed "3,6{/This/d}" pets.txt
echo "对3行到第6行，匹配/This/成功后，再匹配/fish/，成功后执行d命令---------"
sed "3,6{/This/{/fish/d}}" pets.txt
echo "从第一行到最后一行，如果匹配到This，则删除之；如果前面有空格，则去除空格(tab不行，多个空格可以)----"
sed "1,10{/This/d; s/^ *//g}" pets.txt    #NOTE: 用这个例子学习*的作用。

lxw@lxw-PC:~/lxw_Documents$ cat my.txt
This is my cat,my cat‘s name is betty
This is my dog,my dog‘s name is frank
This is my fish,my fish‘s name is george
This is my goat,my goat‘s name is adam

lxw@lxw-PC:~/lxw_Documents$ sed "s/my/your/" my.txt 
This is your cat,my cat‘s name is betty
This is your dog,my dog‘s name is frank
This is your fish,my fish‘s name is george
This is your goat,my goat‘s name is adam

lxw@lxw-PC:~/lxw_Documents$ sed "s/my/your/g" my.txt 
This is your cat,your cat‘s name is betty
This is your dog,your dog‘s name is frank
This is your fish,your fish‘s name is george
This is your goat,your goat‘s name is adam

lxw@lxw-PC:~/lxw_Documents$ sed "N;s/my/your/" my.txt 
This is your cat,my cat‘s name is betty
This is my dog,my dog‘s name is frank
This is your fish,my fish‘s name is george
This is my goat,my goat‘s name is adam

lxw@lxw-PC:~/lxw_Documents$ sed "N;s/my/your/g" my.txt 
This is your cat,your cat‘s name is betty
This is your dog,your dog‘s name is frank
This is your fish,your fish‘s name is george
This is your goat,your goat‘s name is adam

This is my cat,
    my cat‘s name is betty
This is my dog,
    my dog‘s name is frank
This is my fish,
    my fish‘s name is george
This is my goat,
    my goat‘s name is adam

This is my cat, my cat‘s name is betty
This is my dog, my dog‘s name is frank
This is my fish, my fish‘s name is george
This is my goat, my goat‘s name is adam