bash awk 将记录分隔符 (RS) 更改为每 2 行

awk to change the record separator (RS) to every 2 lines

提问by ibcritn

I am wondering how to use Awk to process every 2 lines of data instead of every one. By default the record separator (RS) is set to every new line, how can I change this to every 2 lines.

我想知道如何使用 awk 来处理每 2 行数据而不是每行数据。默认情况下，记录分隔符 (RS) 设置为每个新行，如何将其更改为每 2 行。

回答by Birei

It depends of what you want to achieve, but one way is to use the getlineinstruction. For each line, read next one and save it in a variable. So you will have first line in $0and second one in even_line:

这取决于您想要实现的目标，但一种方法是使用getline指令。对于每一行，阅读下一行并将其保存在一个变量中。所以你将有第一行$0和第二行even_line：

getline even_line

回答by glenn Hymanman

If you want to merge lines, use the pasteutility:

如果要合并行，请使用该paste实用程序：

$ printf "%s\n" one two three four five
one
two
three
four
five

$ printf "%s\n" one two three four five | paste -d " " - -
one two
three four
five 

回答by Theodros Zelleke

Divide&Conquer: do it in two steps:

分而治之：分两步做：

1. use awk to introduce blank line
   to separate each two-line record: NR%2==0 {print ""}
2. pipe to another awk process and
   set record separator to blank line: BEGIN {RS=""}

1. 使用awk引入空行
   来分隔每条两行记录：NR%2==0 {print ""}
2. 管道到另一个 awk 进程并将
   记录分隔符设置为空行：BEGIN {RS=""}

Advantage: In the second awkprocess you have all fields of the two lines accessible as $1 to $NF.

优点：在第二个awk过程中，您可以将两行的所有字段作为$1 to $NF.

awk '{print}; NR%2==0 {print ""}' data | \
awk 'BEGIN {RS=""}; {=;print}'

Note:
$1=$1is used here to enforce an update on $0(the whole record).
This guaranties that the output prints the two-line record on one line.
Once you modify a field in your program when you process the two-line records this is no longer required.

注意：
$1=$1此处用于强制更新$0（整个记录）。
这保证输出在一行上打印两行记录。
一旦在处理两行记录时修改程序中的字段，就不再需要了。

回答by Paused until further notice.

This is a bit hackish, but it's a literal answer to your question:

这有点骇人听闻，但它是对您问题的字面回答：

awk 'BEGIN {RS = "[^\n]*\n[^\n]*\n"} {##代码## = RT; print , $NF}' inputfile

Set the record separator to a regex which matches two lines. Then for each line, set $0to the record terminator (which is what matched the regex in RS). This performs field splitting on FS. The print statement is just a demonstration place holder.

将记录分隔符设置为匹配两行的正则表达式。然后对于每一行，设置$0为记录终止符（它与 中的正则表达式匹配RS）。这对 执行字段拆分FS。打印语句只是一个演示占位符。

Note that $0will contain two newlines, but the fields will not contain any newlines.

请注意，$0将包含两个换行符，但字段将不包含任何换行符。