AWK子字符串一个字符

本文介绍了AWK子字符串一个字符的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

这是columns.txt

Here is columns.txt

aaa bbb 3 ccc ddd 2 eee fff 1 3 3 g 3 hhh i jjj 3 kkk ll 3 mm nn oo 3

我可以找到第二列以"b"开头的行:

I can find the line where second column starts with "b":

awk '{if(substr($2,1,1)=="b") {print $0}}' columns.txt

我可以找到第二列以"bb"开头的行:

I can find the line where second column starts with "bb":

awk '{if(substr($2,1,2)=="bb") {print $0}}' columns.txt

为什么为什么我找不到第二列中第二个字符是"b"的行?:

Why oh why can't I find the line where the second character in the second column is "b"?:

awk '{if(substr($2,2,2)=="b") {print $0}}' columns.txt

awk -W version == GNU Awk 3.1.8

awk -W version == GNU Awk 3.1.8

推荐答案

您可以使用:

awk 'substr($2,2,1) == "b"' columns.txt aaa bbb 3

substr函数的第三个参数为长度字符串.

print是awk中的默认操作.

substr function's 3rd argument is length of the string.

print is default action in awk.