shell中的文本處理工具---grep、sed、awk

1.grep

grep 比對條件 處理檔案
grep root passwd 		#過濾root關鍵字
grep ^root passwd 		#以root開頭
grep root$ passwd 		#以root結尾
grep -i root passwd 	#忽略大小寫
grep -E "\<root" passwd #root字元之前不能有字元
grep -E "root\>" passwd #root字元之後不能有字元
grep -E "\<root\>" passwd  #root前後不能有字元
grep -數字	#顯示過濾行以及上面幾行和下面幾行
grep -n  	#顯示比對的行所在的行号
grep -A  	#顯示過濾行以及下面幾行
grep -B  	#顯示過濾行以及上面幾行
grep -v 	#反向過濾
           

練習

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

           

過濾root在中間的

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

grep字元數量比對規則

^aaa	#以aaa開頭
aaa$ 	#以aaa結尾
w....s 	#w開頭s結尾中間四個任意字元
.....s 	#s結尾前面5個任意字元
*		#字元出現任意次
?		#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字元串出現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

指令格式：

sed 參數 指令 處理對象

sed 參數 處理對象 -f 處理規則檔案

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字元替換

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 
           

練習

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$/ #條件

/條件1|條件2/

/條件1/||/條件2/

/條件1/&&/條件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