删除以shell中的字符开头的行，但保留负值 [英] Remove the lines starting with a character in shell, but preserve the negative values

问题描述

我有数据集：

  file.txt 
 de 
 fds 
 fds 
a 
 sa 
 -1 
 2 
 -3 
 1 
} 
  

我想删除所有以字符或特殊字符开头的行，但保留负值。所以我的outfile是：

  out.txt 
 -1 
 2 
 -3 
 1 
  

这个问题与我之前的一个问题有关删除在shell中的一个字符开始的行，我可以删除所有行包括负号。

我需要修改我的代码。

我的代码：

  grep -E^ [0-9]。*file.txt 
   
 $ div class =h2_lin>解决方案

您可以尝试这样：

  grep'^ * [ -  +] \？[0-9] \ +'file.txt> out.txt 
  

（或）

  grep -E'^ * [ -  +]？[0-9] +'file.txt> out.txt 
  

I have dataset as:

file.txt
de
fds
fds
a
sa
 -1
 2
 -3
 1
}

I would like to delete all the lines starting with characters or special characters, but preserve the negative values. So my outfile is:

out.txt
-1
2
-3
1

This question is related to one of my earlier questions Remove the lines starting with a character in shell with which I can remove all lines starting with a character including negative sign.

I need to modify my code.

my code:

grep -E "^[0-9].*" file.txt

解决方案

You can try like this:

grep '^ *[-+]\?[0-9]\+' file.txt > out.txt

(Or)

grep -E '^ *[-+]?[0-9]+' file.txt > out.txt

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