Question

我有一个包含以下几行的大文本文件：

(total drops) 0
(bytes output) 111
(total drops) 1
(bytes output) 222
(total drops) 3
(bytes output) 333
(total drops) 3
(bytes output) 444
(total drops) 5
(bytes output) 555
(total drops) 8
(bytes output) 6666
(total drops) 9
(bytes output) 777
(total drops) 10
(bytes output) 888
(total drops) 20
(bytes output) 999
<<SNIP>>

我想从顶部开始打印2行，跳过下2行并再次打印2行，依此类推...期望的输出应该是这样的：

(total drops) 0
(bytes output) 111
(total drops) 3
(bytes output) 333
(total drops) 5
(bytes output) 555
(total drops) 9
(bytes output) 777
(total drops) 20
(bytes output) 999

我尝试了各种sed / awk，但仍然无法正确完成...

Answer 1

您可以使用此（确认）

 cat test.txt | awk '{if (((NR % 4)==1) || ((NR % 4)==2)) {print}}'

Answer 2

这应该做到：

awk '((NR+3)%4)<2' file

这是简写

awk '(((NR+3)%4)<2){print}' file

之所以起作用，是因为模函数NR%4返回值0,1,2,3。我们需要移动NR，以使0和1位于正确的位置。因此，我们将3添加到NR中。请参见以下代码：

$ seq 1 10 | awk '{print NR, NR%4, (NR+3)%4}'
1 1 0
2 2 1
3 3 2
4 0 3
5 1 0
6 2 1
7 3 2
8 0 3
9 1 0
10 2 1

Answer 3

同样使用Perl，您可以获得所需的输出

> cat  skip_lines.txt
(total drops) 0
(bytes output) 111
(total drops) 1
(bytes output) 222
(total drops) 3
(bytes output) 333
(total drops) 3
(bytes output) 444
(total drops) 5
(bytes output) 555
(total drops) 8
(bytes output) 6666
(total drops) 9
(bytes output) 777
(total drops) 10
(bytes output) 888
(total drops) 20
(bytes output) 999
> perl -ne ' print if $.%4==1 or $.%4==2 ' skip_lines.txt
(total drops) 0
(bytes output) 111
(total drops) 3
(bytes output) 333
(total drops) 5
(bytes output) 555
(total drops) 9
(bytes output) 777
(total drops) 20
(bytes output) 999
>

Linux在文本文件中打印备用2行

3 个答案: