在awk中设置一个外部变量 [英] Set an external variable in awk

问题描述

我编写了一个脚本，其中我要计算data.txt中的列数.我的问题是我无法在awk脚本中设置x. 任何帮助将不胜感激.

I have written a script in which I want to count the number of columns in data.txt . My problem is I am unable to set the x in awk script. Any help would be highly appreciated.

while read p; do
  x=1;
  echo $p | awk -F' ' '{x=NF}'
  echo $x;
  file="$x"".txt";
  echo $file;
  done <$1

data.txt文件:

data.txt file:

4495125 94307025    [e-mail]   94307025.094307025  12443
stazla  [e-mail]  1992/.:\1
1447585 [e-mail] h1st@1
saknit  [e-mail]   1233    1990

预期输出:

5.txt
3.txt
3.txt
4.txt

我的输出:

1.txt
1.txt
1.txt
1.txt

推荐答案

您只是不能将Awk中设置的变量导入到shell上下文中.在您的示例中，在包含NF的x内部设置的值不会在外部反映出来.

You just cannot import variable set in Awk to a shell context. In your example the value set inside x containing NF will be not reflected outside.

您需要使用命令替换($(..))语法来获取NF的值，并在以后使用它

Either you need to use command substitution($(..)) syntax to get the value of NF and use it later

x=$(echo "$p" | awk '{print NF}')

现在x将在每一行中包含列数.请注意，您不需要使用-F' '，它是awk中的默认定界符.

Now x will contain the column count in each of the line. Note that you don't need to use -F' ' which is the default de-limiter in awk.

除了您的要求之外，完全可以在Awk本身中完成.

Besides your requirement can be fully done in Awk itself.

awk 'NF{print NF".txt"}' file

此处，NF{..}是为了确保{..}内部的操作仅应用于非空行.对于每行，我们将打印长度，并在其后附加扩展名.txt.

Here the NF{..} is to ensure that the actions inside {..} are applied only to non-empty rows. The for each row we print the length and append the extension .txt along with it.

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