grep 、sed、awk的一些应用

心已赠人 2022-06-16 23:18 224阅读 0赞

目录： 1、不显示文件中的空行  2、删除文件的1到5行     3、删除文件注释行   4、打印匹配行 5、显示从字符1到字符2的中间行 6、匹配特别表达式   7、替代文本

1、不显示文件中的空行  
\[guo@guo ~\]$ cat rc.local  
\#!/bin/sh  
\#  
\# This script will be executed \*after\* all the other init scripts.  
\# You can put your own initialization stuff in here if you don't  
\# want to do the full Sys V style init stuff.  
  
touch /var/lock/subsys/local  
\[guo@guo ~\]$ grep -v '^$' rc.local  
\#!/bin/sh  
\#  
\# This script will be executed \*after\* all the other init scripts.  
\# You can put your own initialization stuff in here if you don't  
\# want to do the full Sys V style init stuff.  
touch /var/lock/subsys/local  
\[guo@guo ~\]$ sed -e '/^$/d' rc.local  
\#!/bin/sh  
\#  
\# This script will be executed \*after\* all the other init scripts.  
\# You can put your own initialization stuff in here if you don't  
\# want to do the full Sys V style init stuff.  
touch /var/lock/subsys/local  
\[guo@guo ~\]$ awk '!/^$/\{print $0 \}' rc.local  
\#!/bin/sh  
\#  
\# This script will be executed \*after\* all the other init scripts.  
\# You can put your own initialization stuff in here if you don't  
\# want to do the full Sys V style init stuff.  
touch /var/lock/subsys/local  
2、删除文件的1到5行  
\[guo@guo ~\]$ cat test  
root:x:0:0:root:/root:/bin/bash  
bin:x:1:1:bin:/bin:/sbin/nologin  
daemon:x:2:2:daemon:/sbin:/sbin/nologin  
adm:x:3:4:adm:/var/adm:/sbin/nologin  
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin  
sync:x:5:0:sync:/sbin:/bin/sync  
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown  
halt:x:7:0:halt:/sbin:/sbin/halt  
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin  
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin  
\[guo@guo ~\]$ sed -e '1,5d' test  
sync:x:5:0:sync:/sbin:/bin/sync  
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown  
halt:x:7:0:halt:/sbin:/sbin/halt  
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin  
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin  
\[guo@guo ~\]$ awk '\{if(NR>5 ) print $0\} ' test  
sync:x:5:0:sync:/sbin:/bin/sync  
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown  
halt:x:7:0:halt:/sbin:/sbin/halt  
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin  
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin  
3、删除文件注释行  
\[guo@guo ~\]$ sed -e "/^\#/d" rc.local  
  
touch /var/lock/subsys/local  
\[guo@guo ~\]$ awk '!/^\#/\{print $0\}' rc.local  
  
touch /var/lock/subsys/local  
\[guo@guo ~\]$ grep -v '^\#' rc.local  
  
touch /var/lock/subsys/local  
4、打印匹配行  
\[guo@guo ~\]$ grep '^\#' rc.local  
\#!/bin/sh  
\#  
\# This script will be executed \*after\* all the other init scripts.  
\# You can put your own initialization stuff in here if you don't  
\# want to do the full Sys V style init stuff.  
\[guo@guo ~\]$ sed -n -e '/^\#/p' rc.local  
\#!/bin/sh  
\#  
\# This script will be executed \*after\* all the other init scripts.  
\# You can put your own initialization stuff in here if you don't  
\# want to do the full Sys V style init stuff.  
\[guo@guo ~\]$ awk ' /^\#/ \{ print $0 \}' rc.local  
\#!/bin/sh  
\#  
\# This script will be executed \*after\* all the other init scripts.  
\# You can put your own initialization stuff in here if you don't  
\# want to do the full Sys V style init stuff.  
5、显示从字符1到字符2的中间行  
\[guo@guo ~\]$ cat test1  
good  
hello  
hi  shell  
sorry  
goodbye c  
\[guo@guo ~\]$ sed -n -e '/hello/,/sorry/p' test1  
hello  
hi  shell  
sorry  
\[guo@guo ~\]$ awk '/hello/,/sorry/ \{print $0 \}' test1  
hello  
hi  shell  
sorry  
6、匹配特别表达式  
\[guo@guo ~\]$ cat for.c  
\#include<stdio.h>  
main()  
\{  
    printf("Hello Shell");  
\}  
\[guo@guo ~\]$ sed -n -e '/main\[\[:space:\]\]\*(/,/^\}/p' for.c  
main()  
\{  
    printf("Hello Shell");  
\}  
7、替代文本  
\[guo@guo ~\]$ cat test |tr 'root' 'good'  
good:x:0:0:good:/good:/bin/bash  
bin:x:1:1:bin:/bin:/sbin/nologin  
daemon:x:2:2:daemon:/sbin:/sbin/nologin  
adm:x:3:4:adm:/vag/adm:/sbin/nologin  
lp:x:4:7:lp:/vag/spool/lpd:/sbin/nologin  
sync:x:5:0:sync:/sbin:/bin/sync  
shuddown:x:6:0:shuddown:/sbin:/sbin/shuddown  
hald:x:7:0:hald:/sbin:/sbin/hald  
mail:x:8:12:mail:/vag/spool/mail:/sbin/nologin  
uucp:x:10:14:uucp:/vag/spool/uucp:/sbin/nologin  
\[guo@guo ~\]$ cat test |tr 'root' 'god'  
gddd:x:0:0:gddd:/gddd:/bin/bash  
bin:x:1:1:bin:/bin:/sbin/ndldgin  
daemdn:x:2:2:daemdn:/sbin:/sbin/ndldgin  
adm:x:3:4:adm:/vag/adm:/sbin/ndldgin  
lp:x:4:7:lp:/vag/spddl/lpd:/sbin/ndldgin  
sync:x:5:0:sync:/sbin:/bin/sync  
shudddwn:x:6:0:shudddwn:/sbin:/sbin/shudddwn  
hald:x:7:0:hald:/sbin:/sbin/hald  
mail:x:8:12:mail:/vag/spddl/mail:/sbin/ndldgin  
uucp:x:10:14:uucp:/vag/spddl/uucp:/sbin/ndldgin  
\[guo@guo ~\]$ sed 's/root/good/p' test  
good:x:0:0:root:/root:/bin/bash  
good:x:0:0:root:/root:/bin/bash  
bin:x:1:1:bin:/bin:/sbin/nologin  
daemon:x:2:2:daemon:/sbin:/sbin/nologin  
adm:x:3:4:adm:/var/adm:/sbin/nologin  
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin  
sync:x:5:0:sync:/sbin:/bin/sync  
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown  
halt:x:7:0:halt:/sbin:/sbin/halt  
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin  
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin  
\[guo@guo ~\]$ sed 's/root/god/p' test  
god:x:0:0:root:/root:/bin/bash  
god:x:0:0:root:/root:/bin/bash  
bin:x:1:1:bin:/bin:/sbin/nologin  
daemon:x:2:2:daemon:/sbin:/sbin/nologin  
adm:x:3:4:adm:/var/adm:/sbin/nologin  
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin  
sync:x:5:0:sync:/sbin:/bin/sync  
  
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown  
halt:x:7:0:halt:/sbin:/sbin/halt  
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin  
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin  
\[guo@guo ~\]$ awk '\{gsub(/root/,"good");print $0\}' test  
good:x:0:0:good:/good:/bin/bash  
bin:x:1:1:bin:/bin:/sbin/nologin  
daemon:x:2:2:daemon:/sbin:/sbin/nologin  
adm:x:3:4:adm:/var/adm:/sbin/nologin  
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin  
sync:x:5:0:sync:/sbin:/bin/sync  
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown  
halt:x:7:0:halt:/sbin:/sbin/halt  
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin  
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin  
\[guo@guo ~\]$ awk '\{gsub(/root/,"god");print $0\}' test  
god:x:0:0:god:/god:/bin/bash  
bin:x:1:1:bin:/bin:/sbin/nologin  
daemon:x:2:2:daemon:/sbin:/sbin/nologin  
adm:x:3:4:adm:/var/adm:/sbin/nologin  
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin  
sync:x:5:0:sync:/sbin:/bin/sync  
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown  
halt:x:7:0:halt:/sbin:/sbin/halt  
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin  
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin  
通过对比可知tr的替换两个字串必须等长度，而sed不能把说有的root替换  
\[guo@guo ~\]$ sed 's/root/good/g' test  
good:x:0:0:good:/good:/bin/bash  
bin:x:1:1:bin:/bin:/sbin/nologin  
daemon:x:2:2:daemon:/sbin:/sbin/nologin  
adm:x:3:4:adm:/var/adm:/sbin/nologin  
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin  
sync:x:5:0:sync:/sbin:/bin/sync  
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown  
halt:x:7:0:halt:/sbin:/sbin/halt  
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin  
uucp:x:10:14:uucp:/var/spool/uucp:/sbin/nologin  
通过参数g实现把每个root都替换