shell对文件的操作（sed命令详解以及如何搭建ftp服务）
一、简介
在shell脚本编写中，时常会用到对文件的相关操作，比如增加内容，修改内容，删除部分内容，查看部分内容等，但是上述举例的这些操作一般都是需要在文本编辑器中才能操作，常用的文本编辑器如：gedit、vim、nano等又是交互式文本编辑器，脚本无法自己独立完成，必须有人参与才可以完成。如果这样的话又违背了我们编写脚本的意愿(全部由机器来完成，减少人的工作压力，提升工作效率)。emm…如何才能让这些操作全部脚本自己就搞定，而不需要人的参与，而且又能按照我们的脚本预案来完成呢？
为了解决上述问题，linux为大家提供了一些命令，比如Perl、sed等命令，着重介绍一下sed命令。
二、sed命令
1、sed介绍
sed是linux中提供的一个外部命令,它是一个行(流)编辑器，非交互式的对文件内容进行增删改查的操作，使用者只能在命令行输入编辑命令、指定文件名，然后在屏幕上查看输出。它和文本编辑器有本质的区别。
区别是： 文本编辑器: 编辑对象是文件 行编辑器：编辑对象是文件中的行 也就是前者一次处理一个文本，而后者是一次处理一个文本中的一行。这个是我们应该弄清楚且必须牢记的，否者可能无法理解sed的运行原理和使用精髓。
sed数据处理原理：
2、sed语法
sed 命令语法：
sed [options] ‘{command}[flags]’ [filename]
命令选项：
-e script 将脚本中指定的命令添加到处理输入时执行的命令中 多条件，一行中要有多个操作
-f script 将文件中指定的命令添加到处理输入时执行的命令中
-n 抑制自动输出
-i 编辑文件内容
-i.bak 修改时同时创建.bak备份文件。
-r 使用扩展的正则表达式
! 取反 （跟在模式条件后与shell有所区别）
command 对文件干什么
sed常用内部命令
a 在匹配后面添加
i 在匹配前面添加
d 删除
s 查找替换 字符串
c 更改
y 转换 N D P
p 打印
#flags
数字 表示新文本替换的模式
g： 表示用新文本替换现有文本的全部实例
p： 表示打印原始的内容
w filename: 将替换的结果写入文件
3，演示示例
先准备一个文件
（1）command演示
[root@CentOs shell]# vim data1 the quick brown fox jumps over the lazy dog.
2 the quick brown fox jumps over the lazy dog.
3 the quick brown fox jumps over the lazy dog.
4 the quick brown fox jumps over the lazy dog.
5 the quick brown fox jumps over the lazy dog.
a添加后面命令：
[root@CentOs shell]# sed 'a\hello,world' data
1 the quick brown fox jumps over the lazy dog.
hello,world
2 the quick brown fox jumps over the lazy dog.
hello,world
3 the quick brown fox jumps over the lazy dog.
hello,world
4 the quick brown fox jumps over the lazy dog.
hello,world
5 the quick brown fox jumps over the lazy dog.
hello,world
[root@CentOs shell]#
[root@CentOs shell]# sed '3a\hello,world' data （对第三行追加）
1 the quick brown fox jumps over the lazy dog.
2 the quick brown fox jumps over the lazy dog.
3 the quick brown fox jumps over the lazy dog.
hello,world
4 the quick brown fox jumps over the lazy dog.
5 the quick brown fox jumps over the lazy dog.
[root@CentOs shell]#
[root@CentOs shell]# sed '2,4a\hello,world' data
1 the quick brown fox jumps over the lazy dog.
2 the quick brown fox jumps over the lazy dog.
hello,world
3 the quick brown fox jumps over the lazy dog.
hello,world
4 the quick brown fox jumps over the lazy dog.
hello,world
5 the quick brown fox jumps over the lazy dog.
[root@CentOs shell]#
[root@CentOs shell]# sed '/3 the/a\hello,world' data （“//”是开启匹配模式，这个生产环境中常用！！！）
1 the quick brown fox jumps over the lazy dog.
2 the quick brown fox jumps over the lazy dog.
3 the quick brown fox jumps over the lazy dog.
hello,world
4 the quick brown fox jumps over the lazy dog.
5 the quick brown fox jumps over the lazy dog.
[root@CentOs shell]#
i插入前面命令：
[root@CentOs shell]# sed '/3 the/i\hello,world' data
1 the quick brown fox jumps over the lazy dog.
2 the quick brown fox jumps over the lazy dog.
hello,world
3 the quick brown fox jumps over the lazy dog.
4 the quick brown fox jumps over the lazy dog.
5 the quick brown fox jumps over the lazy dog.
[root@CentOs shell]#
d删除命令：
[root@CentOs shell]# sed '/3 the/d' data
1 the quick brown fox jumps over the lazy dog.
2 the quick brown fox jumps over the lazy dog.
4 the quick brown fox jumps over the lazy dog.
5 the quick brown fox jumps over the lazy dog.
[root@CentOs shell]# cp /usr/local/nginx/conf/nginx.conf .
[root@CentOs shell]# sed -r '/^#/d' nginx.conf （删除以#开头的行）
[root@CentOs shell]# sed -r '/(^#|#|^$)/d' nginx.conf （删除以#开头或者包含#或者空行的行）
worker_processes 1;
events {
worker_connections 1024;
}
http {
include mime.types;
default_type application/octet-stream;
sendfile on;
keepalive_timeout 65;
server {
listen 80;
server_name localhost;
location / {
root html;
index index.html index.htm;
}
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root html;
}
}
}
[root@CentOs shell]#
s替换命令：
[root@CentOs shell]# cat data
1 the quick brown fox jumps over the lazy dog.
2 the quick brown fox jumps over the lazy dog.
3 the quick brown fox jumps over the lazy dog.
4 the quick brown fox jumps over the lazy dog.
5 the quick brown fox jumps over the lazy dog.
[root@CentOs shell]# sed 's/dog/cat/' data （把dog替换成cat）
1 the quick brown fox jumps over the lazy cat.
2 the quick brown fox jumps over the lazy cat.
3 the quick brown fox jumps over the lazy cat.
4 the quick brown fox jumps over the lazy cat.
5 the quick brown fox jumps over the lazy cat.
[root@CentOs shell]#
[root@CentOs shell]# sed '/3 the/s/dog/cat/' data
1 the quick brown fox jumps over the lazy dog.
2 the quick brown fox jumps over the lazy dog.
3 the quick brown fox jumps over the lazy cat.
4 the quick brown fox jumps over the lazy dog.
5 the quick brown fox jumps over the lazy dog.
[root@CentOs shell]#
c更改命令
[root@CentOs shell]# sed '/3 the/c\hello world' data
1 the quick brown fox jumps over the lazy dog.
2 the quick brown fox jumps over the lazy dog.
hello world
4 the quick brown fox jumps over the lazy dog.
5 the quick brown fox jumps over the lazy dog.
[root@CentOs shell]#
[root@CentOs shell]# sed '2,4c\hello world' data（这个有点特殊，把2-4行删除，再添加）
1 the quick brown fox jumps over the lazy dog.
hello world
5 the quick brown fox jumps over the lazy dog.
[root@CentOs shell]#
y转换命令：
[root@CentOs shell]# sed 'y/abcdefg/ABCDEFG/' data
1 thE quiCk Brown Fox jumps ovEr thE lAzy DoG.
2 thE quiCk Brown Fox jumps ovEr thE lAzy DoG.
3 thE quiCk Brown Fox jumps ovEr thE lAzy DoG.
4 thE quiCk Brown Fox jumps ovEr thE lAzy DoG.
5 thE quiCk Brown Fox jumps ovEr thE lAzy DoG.
[root@CentOs shell]#
p打印命令
[root@CentOs shell]# sed 'p' data （出现两行，是因为把内存和文件都打印了出来！！！）
1 the quick brown fox jumps over the lazy dog.
1 the quick brown fox jumps over the lazy dog.
2 the quick brown fox jumps over the lazy dog.
2 the quick brown fox jumps over the lazy dog.
3 the quick brown fox jumps over the lazy dog.
3 the quick brown fox jumps over the lazy dog.
4 the quick brown fox jumps over the lazy dog.
4 the quick brown fox jumps over the lazy dog.
5 the quick brown fox jumps over the lazy dog.
5 the quick brown fox jumps over the lazy dog.
[root@CentOs shell]#
[root@CentOs shell]# sed '/3 the/p' data
1 the quick brown fox jumps over the lazy dog.
2 the quick brown fox jumps over the lazy dog.
3 the quick brown fox jumps over the lazy dog.
3 the quick brown fox jumps over the lazy dog.
4 the quick brown fox jumps over the lazy dog.
5 the quick brown fox jumps over the lazy dog.
[root@CentOs shell]#
（2）flags演示
数字：
[root@CentOs shell]# cat data
1 the quick brown fox jumps over the lazy dog.dog
2 the quick brown fox jumps over the lazy dog.dog
3 the quick brown fox jumps over the lazy dog.dog
4 the quick brown fox jumps over the lazy dog.dog
5 the quick brown fox jumps over the lazy dog.dog
[root@CentOs shell]# sed 's/dog/cat/' data
1 the quick brown fox jumps over the lazy cat.dog
2 the quick brown fox jumps over the lazy cat.dog
3 the quick brown fox jumps over the lazy cat.dog
4 the quick brown fox jumps over the lazy cat.dog
5 the quick brown fox jumps over the lazy cat.dog
[root@CentOs shell]# sed 's/dog/cat/2' data
1 the quick brown fox jumps over the lazy dog.cat
2 the quick brown fox jumps over the lazy dog.cat
3 the quick brown fox jumps over the lazy dog.cat
4 the quick brown fox jumps over the lazy dog.cat
5 the quick brown fox jumps over the lazy dog.cat
[root@CentOs shell]#
g：全部替换
[root@CentOs shell]# sed 's/dog/cat/g' data
1 the quick brown fox jumps over the lazy cat.cat
2 the quick brown fox jumps over the lazy cat.cat
3 the quick brown fox jumps over the lazy cat.cat
4 the quick brown fox jumps over the lazy cat.cat
5 the quick brown fox jumps over the lazy cat.cat
[root@CentOs shell]#
p：打印输出
[root@CentOs shell]# sed '3s/dog/cat/p' data
1 the quick brown fox jumps over the lazy dog.dog
2 the quick brown fox jumps over the lazy dog.dog
3 the quick brown fox jumps over the lazy cat.dog
3 the quick brown fox jumps over the lazy cat.dog
4 the quick brown fox jumps over the lazy dog.dog
5 the quick brown fox jumps over the lazy dog.dog
[root@CentOs shell]#
w filename：将替换的结果写入文件中
[root@CentOs shell]# sed '3s/dog/cat/w newfile data
1 the quick brown fox jumps over the lazy dog.dog
2 the quick brown fox jumps over the lazy dog.dog
3 the quick brown fox jumps over the lazy cat.dog
4 the quick brown fox jumps over the lazy dog.dog
5 the quick brown fox jumps over the lazy dog.dog
[root@CentOs shell]# ls
data ip.txt nginx.conf ShellTest.sh zzku.sh
fenjie.txt newfile NginxTestfailing.sh test01.sh
[root@CentOs shell]# cat newfile
3 the quick brown fox jumps over the lazy cat.dog
[root@CentOs shell]#
（3）命令选项
-n：只输入自己想要的那部分
[root@CentOs shell]# sed -n '3s/dog/cat/p' data
3 the quick brown fox jumps over the lazy cat.dog
[root@CentOs shell]#
-e：多条件，一行中要有多个操作
[root@CentOs shell]# sed -e 's/brown/grey/;s/dog/cat/' data
1 the quick grey fox jumps over the lazy cat.dog
2 the quick grey fox jumps over the lazy cat.dog
3 the quick grey fox jumps over the lazy cat.dog
4 the quick grey fox jumps over the lazy cat.dog
5 the quick grey fox jumps over the lazy cat.dog
[root@CentOs shell]#
-f：将文件中的命令添加到处理输入时执行的命令中
[root@CentOs shell]# vim file
[root@CentOs shell]# cat file
s/brown/grey/
s/dog/cat/
[root@CentOs shell]# sed -f file data
1 the quick grey fox jumps over the lazy cat.dog
2 the quick grey fox jumps over the lazy cat.dog
3 the quick grey fox jumps over the lazy cat.dog
4 the quick grey fox jumps over the lazy cat.dog
5 the quick grey fox jumps over the lazy cat.dog
[root@CentOs shell]#
-i：修改源文件（不可逆）
[root@CentOs shell]# sed -i 's/dog/cat/g' data
[root@CentOs shell]# cat data
1 the quick brown fox jumps over the lazy cat.cat
2 the quick brown fox jumps over the lazy cat.cat
3 the quick brown fox jumps over the lazy cat.cat
4 the quick brown fox jumps over the lazy cat.cat
5 the quick brown fox jumps over the lazy cat.cat
[root@CentOs shell]#
[root@CentOs shell]# sed -i.bak 's/cat/dog/g' data（使用-i时，可以备份一个文件）
[root@CentOs shell]# ls
data fenjie.txt ip.txt NginxTestfailing.sh test01.sh
data.bak file nginx.conf ShellTest.sh zzku.sh
[root@CentOs shell]# cat data.bak （源文件的备份还是没有变化）
1 the quick brown fox jumps over the lazy cat.cat
2 the quick brown fox jumps over the lazy cat.cat
3 the quick brown fox jumps over the lazy cat.cat
4 the quick brown fox jumps over the lazy cat.cat
5 the quick brown fox jumps over the lazy cat.cat
[root@CentOs shell]# cat data（源文件已被修改）
1 the quick brown fox jumps over the lazy dog.dog
2 the quick brown fox jumps over the lazy dog.dog
3 the quick brown fox jumps over the lazy dog.dog
4 the quick brown fox jumps over the lazy dog.dog
5 the quick brown fox jumps over the lazy dog.dog
[root@CentOs shell]#
-r：使用正则表达式
[root@CentOs shell]# sed -r -n '/^(root)(.*)(bash)$/p' /etc/passwd（打印以root开头、中间任意、结尾以bash结束的行）
root:x:0:0:root:/root:/bin/bash
[root@CentOs shell]#
！：取反
我们也不一定非得使用文件输出。以管道为例：
[root@CentOs shell]# echo "Tom is cool"|sed 's/Tom is/I am/'
I am cool
[root@CentOs shell]#
三、sed的一些小技巧
$=：统计行号
[root@CentOs shell]# sed -n '$=' data
5
[root@CentOs shell]#
=：给每一行加行号
[root@CentOs shell]# sed '=' data
1
1 the quick brown fox jumps over the lazy dog.dog
2
2 the quick brown fox jumps over the lazy dog.dog
3
3 the quick brown fox jumps over the lazy dog.dog
4
4 the quick brown fox jumps over the lazy dog.dog
5
5 the quick brown fox jumps over the lazy dog.dog
[root@CentOs shell]#
四、写一个搭建ftp服务的脚本
要求如下：
1）不支持本地用户登录 local_enable=NO
2） 匿名用户可以上传 新建 删除 anon_upload_enable=YES anon_mkdir_write_enable=YES
3） 匿名用户限速500KBps anon_max_rate=500000
仅供参考：
#!/bin/bash
ipaddr=`ifconfig eth0|sed -n '2p'|sed -e 's/.*inet addr:\(.*\) Bcast.*/\1/g'`
iptail=`echo $ipaddr|cut -d'.' -f4`
ipremote=192.168.1.10
#修改主机名
hostname server$iptail.zutuanxue.com
sed -i "/HOSTNAME/cHOSTNAME=server$iptail.zutuanxue.com" /etc/sysconfig/network
echo "$ipaddr server$iptail.zutuanxue.cc" >>/etc/hosts
#关闭防火墙和selinux
service iptables stop
setenforce 0 >/dev/null 2>&1
sed -i '/^SELINUX=/cSELINUX=disabled' /etc/selinux/config
#配置yum源(一般是内网源)
#test network
ping -c 1 $ipremote > /dev/null 2>&1
if [ $? -ne 0 ];then
echo "你的网络不通，请先检查你的网络"
exit 1
else
echo "网络ok."
fi
cat > /etc/yum.repos.d/server.repo << end
[server]
name=server
baseurl=ftp://$ipremote
enabled=1
gpgcheck=0
end
#安装软件
read -p "请输入需要安装的软件，多个用空格隔开：" soft
yum -y install $soft &>/dev/null
#备份配置文件
conf=/etc/vsftpd/vsftpd.conf
\cp $conf $conf.default
#根据需求修改配置文件
sed -ir '/^#|^$/d' $conf
sed -i '/local_enable/c\local_enable=NO' $conf
sed -i '$a anon_upload_enable=YES' $conf
sed -i '$a anon_mkdir_write_enable=YES' $conf
sed -i '$a anon_other_write_enable=YES' $conf
sed -i '$a anon_max_rate=512000' $conf
#启动服务
service vsftpd restart &>/dev/null && echo"vsftpd服务启动成功"
#测试验证
chmod 777 /var/ftp/pub
cp /etc/hosts /var/ftp/pub
#测试下载
cd /tmp
lftp $ipaddr <<end
cd pub
get hosts
exit
end
if [ -f /tmp/hosts ];then
echo "匿名用户下载成功"
rm -f /tmp/hosts
else
echo "匿名用户下载失败"
fi
#测试上传、创建目录、删除目录等
cd /tmp
lftp $ipaddr << end
cd pub
mkdir test1
mkdir test2
put /etc/group
rmdir test2
exit
end
if [ -d /var/ftp/pub/test1 ];then
echo "创建目录成功"
if [ ! -d /var/ftp/pub/test2 ];then
echo "文件删除成功"
fi
else
if [ -f /var/ftp/pub/group ];then
echo "文件上传成功"
else
echo "上传、创建目录删除目录部ok"
fi
fi
[ -f /var/ftp/pub/group ] && echo "上传文件成功"
