sed替換

yiguihuo

我想把文件中MASTER替換為BACKUP，同時(shí)BACKUP替換為MASTER，就是MASTER和BACKUP互換
sed 's/MASTER/BACKUP/;s/BACKUP/MASTER/' 1
但我這樣寫(xiě)合著第一次匹配后第二次又匹配回去了，我看了sed的工作原理，是每次讀取一行然后進(jìn)行操作，能不能sed對(duì)一行進(jìn)行操作了后面的命令就不進(jìn)行處理了�；蛴惺裁锤�簡(jiǎn)單的方法可以實(shí)現(xiàn)呢

Shell_HAT

除了keepalived.conf之外，再準(zhǔn)備兩個(gè)文件：
BACKUP.keepalived.conf
MASTER.keepalived.conf

需要切換的時(shí)候直接cp就可以了：
cp -p BACKUP.keepalived.conf keepalived.conf
或者：
cp -p MASTER.keepalived.conf keepalived.conf

goofool

1. sed 's/MASTER/BACKUP/;t;s/BACKUP/MASTER/'

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yiguihuo

2樓這方法真實(shí)簡(jiǎn)單明了，三樓正解

zsszss0000

問(wèn)一下  這里的t;表示什么含義？

Buring__

回復(fù) 5# zsszss0000


    s命令執(zhí)行成功，執(zhí)行t命令，沒(méi)有標(biāo)簽，跳轉(zhuǎn)到命令的結(jié)尾，這樣將會(huì)跳過(guò)后面的s/BACKUP/MASTER/

Herowinter

回復(fù) 3# goofool

1. echo "MASTER BACKUP"|sed 's/MASTER/BACKUP/;t;s/BACKUP/MASTER/'
   
2. BACKUP BACKUP

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dn833

1. [root@FILE_SHARE ~]# cat a
   
2. MASTER BACKUP
   
3. BACKUP MASTER
   
4. [root@FILE_SHARE ~]# tr "MASTER|BACKUP" "BACKUP|MASTER" < a
   
5. BACKUP MASTER
   
6. MASTER BACKUP

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goofool

回復(fù) 7# Herowinter


    這種情況應(yīng)該可以建立個(gè)中間變量，然后再轉(zhuǎn)回去，但是配置文件應(yīng)該不會(huì)兩個(gè)關(guān)鍵字在一行吧。

1. wang@dean:~$ echo -e "A B B\nB A A\nA\nB" | sed -r 's/A/\\A/g;s/B/A/g;s/\\A/B/g'
   
2. B A A
   
3. A B B
   
4. B
   
5. A

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Herowinter

回復(fù) 9# goofool


Yes, this is the common sed solution for this problem.
Similar as following code.

1. echo -e "MASTER BACKUP MASTER\nBACKUP MASTER BACKUP"|sed 's/MASTER/\n/g;s/BACKUP/MASTER/g;s/\n/BACKUP/g'
   
2. BACKUP MASTER BACKUP
   
3. MASTER BACKUP MASTER

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