一线可打印两个图案之间的所有线条 [英] One-liner to print all lines between two patterns

问题描述

使用一行Perl代码，最简单的方法是打印两个模式之间的所有行(不包括带有模式的行)吗?

Using one line of Perl code, what is the shortest way possible to print all the lines between two patterns not including the lines with the patterns?

如果这是file.txt:

If this is file.txt:

aaa
START
bbb
ccc
ddd
END
eee
fff

我要打印此:

bbb
ccc
ddd

我可以使用以下方法获得大部分信息:

I can get most of the way there using something like this:

perl -ne 'print if (/^START/../^END/);'

不过，其中包括START和END行.

我可以像这样完成工作:

I can get the job done like this:

perl -ne 'if (/^START/../^END/) { print unless (/^(START)|(END)/); };' file.txt

但这似乎是多余的.

我真正想做的是使用像这样的lookbehind和lookahead断言:

What I'd really like to do is use lookbehind and lookahead assertions like this:

perl -ne 'print if (/^(?<=START)/../(?=END)/);' file.txt

但这是行不通的，我认为我的正则表达式有些错误.

But that doesn't work and I think I've got something just a little bit wrong in my regex.

这些只是我尝试过的一些不产生任何输出的变体:

These are just some of the variations I've tried that produce no output:

perl -ne 'print if (/^(?<=START)/../^.*$(?=END)/);' file.txt
perl -ne 'print if (/^(?<=START)/../^.*(?=END)/);' file.txt
perl -ne 'print if (/^(?<=START)/../(?=END)/);' file.txt
perl -ne 'print if (/^(?<=START)/../.*(?=END)/);' file.txt
perl -ne 'print if (/^(?<=START)/../^.*(?=END)/);' file.txt
perl -ne 'print if (/^(?<=START)/../$(?=END)/);' file.txt
perl -ne 'print if (/^(?<=START)/../^(?=END)/);' file.txt
perl -ne 'print if (/^(?<=START)/../(?=^END)/);' file.txt
perl -ne 'print if (/^(?<=START)/../.*(?=END)/s);' file.txt

推荐答案

读取整个文件，进行匹配并打印.

Read the whole file, match, and print.

perl -0777 -e 'print <> =~ /START.*?\n(.*?)END.*?/gs;' file.txt

如果单独在线，可能会在START|END之后下降.*?. 然后将\n放到各段之间的空白行.

May drop .*? after START|END if alone on line. Then drop \n for a blank line between segments.

读取文件，用START|END分隔行，打印@F的所有奇数

Read file, split line by START|END, print every odd of @F

perl -0777 -F"START|END" -ane 'print @F[ grep { $_ & 1 } (0..$#F) ]' file.txt

---

使用END { }块进行额外的处理.将}{用于END { }.

---

Use END { } block for extra processing. Uses }{ for END { }.

perl -ne 'push @r, $_ if (/^START/../^END/); }{ print "@r[1..$#r-1]"' file.txt

仅在文件中的单个此类段中起作用.

Works as it stands only for a single such segment in the file.

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