bash 匹配后替换行
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Replace line after match
提问by Steven Penny
Given this file
鉴于此文件
$ cat foo.txt AAA 111 BBB 222 CCC 333
I would like to replace the first line after BBBwith 999. I came up with this command
我想BBB用999. 我想出了这个命令
awk '/BBB/ {f=1; print; next} f {=999; f=0} 1' foo.txt
but I am curious to any shorter commands with either awk or sed.
但我对 awk 或 sed 的任何更短的命令感到好奇。
回答by Jotne
This is some shorter:
这是一些更短的：
awk 'f{sed '/BBB/!b;n;c999' file
="999";f=0}/BBB/{f=1}1' file
f {$0="999";f=0}if fis true, set line to 999and fto 0/BBB/ {f=1}if pattern match set fto 11print all lines, since 1is always true.
f {$0="999";f=0}如果f是真的，集线999，并f以0/BBB/ {f=1}如果模式匹配集f来11打印所有行，因为1始终是真实的。
回答by potong
This might work for you (GNU sed)
这可能对你有用（GNU sed）
$ awk '{print (f?999:sed '/BBB/{n;s/.*/999/}'
); f=0} /BBB/{f=1}' file
AAA
111
BBB
999
CCC
333
If a line contains BBB, print that line and then change the following line to 999.
如果一行包含BBB，则打印该行，然后将下一行更改为999。
!bnegates the previous address (regexp) and breaks out of any processing, ending the sed commands, nprints the current line and then reads the next into the pattern space, cchanges the current line to the string following the command.
!b否定前一个地址 (regexp) 并中断任何处理，结束 sed 命令，n打印当前行，然后将下一行读入模式空间，c将当前行更改为命令后面的字符串。
回答by Ed Morton
awk '/BBB/{print;getline;sed 's/\(BBB\)/\
999/'
="999"}1' your_file
回答by ray
can use sed also, it's shorter
也可以使用 sed，它更短
##代码##回答by Vijay
回答by toph
works on mac
适用于 mac
