shell中的文本处理工具---grep、sed、awk

1.grep

grep 匹配条件 处理文件
grep root passwd 		#过滤root关键字
grep ^root passwd 		#以root开头
grep root$ passwd 		#以root结尾
grep -i root passwd 	#忽略大小写
grep -E "\<root" passwd #root字符之前不能有字符
grep -E "root\>" passwd #root字符之后不能有字符
grep -E "\<root\>" passwd  #root前后不能有字符
grep -数字	#显示过滤行以及上面几行和下面几行
grep -n  	#显示匹配的行所在的行号
grep -A  	#显示过滤行以及下面几行
grep -B  	#显示过滤行以及上面几行
grep -v 	#反向过滤
           

练习

grep root passwd 
grep ^root passwd 
grep root$ passwd 
grep -i root passwd 
grep -E "\<root" passwd 
grep -E "root\>" passwd 
grep -E "\<root\>" passwd 
grep -2 root passwd 
grep -n root passwd 
grep -A2 root passwd 
grep -B2 root passwd 
grep -v root passwd 
grep -E "bash|root" passwd 
grep -E "bash|root" passwd -v

           

过滤root在中间的

grep root passwd  | grep -E "^root|root$" -v
           

grep字符数量匹配规则

^aaa	#以aaa开头
aaa$ 	#以aaa结尾
w....s 	#w开头s结尾中间四个任意字符
.....s 	#s结尾前面5个任意字符
*		#字符出现任意次
?		#0到1次
+		#1到任意次
{n} 	#n次
{m,n} 	#m到n次
{0,n} 	#0-n次
{,n} 	#0-n次
{m,}    #最少m次                                                        
(bu){2}	#bu字符串出现2次
           

grep r.t passwd 
grep r...t passwd 
grep r..t passwd 
grep r*t passwd 
grep r.*t passwd 
grep ro*t passwd 
grep -E "ro?t" passwd 
grep -E "ro{,1}t" passwd 
grep -E "ro{1,}t" passwd 
grep -E "ro{2,3}t" passwd 
           

grep -E "ros*t" passwd 
grep -E "r(os)*t" passwd 
grep -E "r(os){3}t" passwd 
grep -E "r(os){2}t" passwd 
           

2.sed

命令格式：

sed 参数 命令 处理对象

sed 参数 处理对象 -f 处理规则文件

sed 's/sbin/pppp/g' /mnt/passwd
           

vim rule

s/pppp/sbin/g

sed 5p buuu
sed -n 5p buuu

           

cd /mnt
cp /etc/passwd .
ls
vim passwd 

sed '5a hello westos' passwd 
sed '/sync/a hello westos' passwd 
sed '$a hello westos' passwd 
sed '1,5a hello westos' passwd 
sed -e '1a hello westos' -e '5a hello westos' passwd 
sed '5c hello westos' passwd 
sed '/sbin/c helo westos' passwd 
sed '5w westos' passwd 
ls
cat westos 
sed '/sbin/w westos' passwd 
ls
cat westos 
vim aaa
cat aaa
sed '5r aaa' passwd 
sed '$r aaa' passwd 
sed '1r aaa' passwd 
sed '1r passwd' aaa
sed '5i hello westos' passwd 
           

sed字符替换

sed 's/:/###/g' passwd 
sed -e 's/sbin/westos/g;s/nologin/lee/g' passwd 
sed -e '2,5s/sbin/westos/g;s/nologin/lee/g' passwd 
sed -e '/adm/,/lp/s/sbin/westos/g' passwd 
sed -e 's/\//###/g' passwd 
sed -e 's@/@###@g' passwd 
sed -e 's@/@###@g' -i passwd
cat passwd 
           

练习

vim Apache_port.sh

#!/bin/bash
sed "/^Listen/c Listen $1" -i  /etc/httpd/conf/httpd.conf
           

sed '=' passwd 
sed '$=' passwd 
sed -n '$=' passwd 
sed  '=' passwd | sed 's/\n/ /g'
sed  '=' passwd | sed -e  'N;s/\n/ /g'
sed -n '$=' /etc/passwd 
wc -l passwd 
           

3.awk

awk -F 分割符 BEGIN{} {}END FILENAME

NR

NF

FILENAME

westos

“westos”

/bash$/ #条件

/条件1|条件2/

/条件1/||/条件2/

/条件1/&&/条件2/

awk '{ print NR }' passwd 
awk '{ print $0 }' passwd 
awk '{ print NR " " $0 }' passwd 
awk '{ print NR ":" $0 }' passwd 
awk -F : '{ print NF }' passwd 
awk -F : '{ print "NF" }' passwd 
awk -F : '{ print FILENAME }' passwd 
awk -F : '{ print "FILENAME" }' passwd 
awk -F : '/bash$|sh$/{print $1}' passwd 
awk -F : '/bash$|sh$/&&!/^root/{print $1}' /etc/passwd 
awk -F : '/bash$|sh$/&&!/^root/{print $1$2}' /etc/passwd 
awk -F : '/bash$|sh$/&&!/^root/{print $1":"$2}' /etc/passwd 
awk -F : '$5~/^$/{print}' /etc/passwd 
awk -F : '$5!~/^$/{print}' /etc/passwd 
awk -F : 'BEGIN{print "hello"}$5~/^$/{print}' /etc/passwd 
awk -F : 'BEGIN{print "hello"}$5~/^$/{print}END{print "westos"}' /etc/passwd 
awk -F : 'BEGIN{n=0}$5~/^$/{print}END{print n}' /etc/passwd 
awk -F : 'BEGIN{n=0}$5~/^$/{n++}END{print n}' /etc/passwd