grep使用来自其他文件的单词匹配行中的特定位置 [英] grep matching specific position in lines using words from other file

问题描述

我有2个文件

file1：

  12342015010198765hello 
 12342015010188765hello 
 12342015010178765hello 
  

每行包含固定位置的字段，例如，位置 13 - 17 用于 account_id

file2：

  98765 
 88765 
  

其中包含 account_id s。

在Korn Shell中， strong>我想从file1中打印位于 13 - 17 与file2中的 account_id 之一的行。

我不能这样做

$ p $ grep -f file2 file1


因为file2中的 account_id 可以匹配其他字段

 > ^。{12} 98765. * 
  

但没有用。

解决方案

使用awk

  $ awk'NR == FNR {a [$ 1] = 1 ; next;} substr（$ 0,13,5）在'file2 file1 
 12342015010198765hello 
 12342015010188765hello 
  

工作原理

• NR == FNR {a [$ 1] = 1; next;}

  
  
  

  FNR是从当前文件中读取的行数，NR是读取的总行数远。因此，如果 FNR == NR ，我们读取的第一个文件是 file2 。

  
  
  

  file2中的每个ID都保存在数组 a 中。然后，我们跳过其余的命令并跳转到下一个行。

$ c> substr（$ 0,13,5）在一个




如果我们达到这个命令，我们正在处理第二个文件 file1 。





如果从位置13开始的5个字符长的子字符串位于数组 A 。如果条件为真，则awk将执行打印该行的默认操作。使用grep 使用grep h2>



您提到尝试

  grep'^。{12} 98765. * 'file2 
  

它使用扩展正则表达式语法，这意味着 -E 是必需的。而且，在最后匹配。* 没有任何价值：它总是匹配。因此，试试：



  $ grep -E'^。{12} 98765'file1 
 12342015010198765hello 
  

获得两条线：



  $ grep -E'^。{12} [89] 8765'file1 
 12342015010198765hello 
 12342015010188765hello 
  

这是可行的，因为 [89] 8765 恰好匹配file2中感兴趣的ID。当然，awk解决方案在匹配什么ID方面提供了更大的灵活性。




I have 2 file

file1:

12342015010198765hello
12342015010188765hello
12342015010178765hello

whose each line contains fields at fixed positions, for example, position 13 - 17 is for account_id

file2:

98765
88765

which contains a list of account_ids.

In Korn Shell, I want to print lines from file1 whose position 13 - 17 match one of account_id in file2.

I can't do

grep -f file2 file1

because account_id in file2 can match other fields at other positions.

I have tried using pattern in file2:

^.{12}98765.*

but did not work.

解决方案

Using awk

$ awk 'NR==FNR{a[$1]=1;next;} substr($0,13,5) in a' file2 file1
12342015010198765hello
12342015010188765hello

How it works

• NR==FNR{a[$1]=1;next;}

  FNR is the number of lines read so far from the current file and NR is the total number of lines read so far. Thus, if FNR==NR, we are reading the first file which is file2.

  Each ID in in file2 is saved in array a. Then, we skip the rest of the commands and jump to the next line.

• substr($0,13,5) in a

  If we reach this command, we are working on the second file, file1.

  This condition is true if the 5 character long substring that starts at position 13 is in array a. If the condition is true, then awk performs the default action which is to print the line.

Using grep

You mentioned trying

grep '^.{12}98765.*' file2

That uses extended regex syntax which means that -E is required. Also, there is no value in matching .* at the end: it will always match. Thus, try:

$ grep -E '^.{12}98765' file1
12342015010198765hello

To get both lines:

$ grep -E '^.{12}[89]8765' file1
12342015010198765hello
12342015010188765hello

This works because [89]8765 just happens to match the IDs of interest in file2. The awk solution, of course, provides more flexibility in what IDs to match.

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