在文本文件中，如何删除紧随其后的行的所有行子集？

Question

In a text file, I need to delete lines that are exactly beginning like the next line. See example below.

Input:

I like
I like apples
I like apples and oranges
more
more everyday
more everyday
more everyday the more
more everyday the more I play
I
I like

Output:

I like apples and oranges
more everyday the more I play
I like

Answer 1

One way:

$ perl -lne 'print $last unless /^\Q$last/; $last = $_;
             END { print $last }' input.txt
I like apples and oranges
more everyday the more I play
I like

Answer 2

这个sed过滤器读取下一行并删除前一行，只要它匹配：

sed ':0;N;s/^\(.*\)\n\1/\1/;t0;P;D'