shell关于区域内替换的求助大神！！

rediculous2014

假设有这样一个text文件
aaa
bbb
aaa
ddd
aaa
eee
如果我只想将第三个aaa替换成ccc肿么破？

moperyblue

1. awk '/aaa/{++i;f=1}i==3&&f{$0="ccc";f=0}1'
   
2. sed ':a;N;$!ba;s/aaa/ccc/3'
   
3. sed -z 's/aaa/ccc/3' #sed 4.2.2
   
4. sed -r '/aaa/{x;s/^/./;/^.{3}$/{x;s/.*/ccc/;b};x}'
   

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liion631818

1. @ubuntu:~/shell$ echo 'aaa
   
2. bbb
   
3. aaa
   
4. ddd
   
5. aaa
   
6. eee' | sed '/aaa/{H;x;/^\n.\+\n.\+\n[^\n]\+$/{s/.*/ccc/p;d};x}'
   
7. aaa
   
8. bbb
   
9. aaa
   
10. ddd
    
11. ccc
    
12. eee

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回复 1# rediculous2014


   

ll104567

awk '/aaa/{a++}{if(a!=3){print $0}else{print "ccc";a=4}}'

sunzhiguolu

1. 
   
2. perl -nle 'if(/\Aaaa/ and ++$n==3){print "ccc";next}print' f
   

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hz_oracle

awk '/aaa/{s++}s==3{gsub("aaa","ccc")}{print $0}' file

jcdiy0601

1. awk '/aaa/{num+=1;if(num==3)gsub("aaa","ccc",$0)}{print}' file

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关阴月飞

1. awk  '$0=gensub(/aaa/,"ccc",3)'  RS=  urfile

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杰瑞26

1. root@localhost:~/training# cat text | grep aaa | sed '3 s:aaa:ccc:'
   
2. aaa
   
3. aaa
   
4. ccc
   

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hjfeng1988

@关阴月飞
RS＝放在前面得用vRS=，这是什么梗