如何用sed删除每隔一行? [英] How to remove every other line with sed?

问题描述

如何使用 sed 删除所有奇数行?

How can I remove every odd line, using sed?

remove
keep
remove
keep
remove
...

推荐答案

GNU sed 有一个合适的寻址模式:

GNU sed has a suitable addressing mode:

sed -n '1~2!p' file

这意味着，从第 1 行开始，到第 2 步，打印所有其他行.

which means, starting from line 1, and with step 2, print all other lines.

等效地，您可以删除 -n，并删除匹配的行:

Equivalently, you can drop the -n, and delete matching lines:

sed '1~2d'

也可以使用awk来完成:

It can also be done using awk:

awk 'NR%2==0' file

(当行号是 2 的倍数时，打印该行)

(Whenever line number is a multiple of 2, print the line)

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