如何grep和执行一个命令（对于每一场比赛） [英] How to grep and execute a command (for every match)

问题描述

如何在一个文件中grep并为每个匹配执行一个命令？

文件：

  foo 
 bar 
 42 
 foo 
 bar 
  

我想为 foo 中的每个匹配执行例如 date 。

以下尝试不起作用：

  grep file foo |日期％s。％N 
  

如何做？

解决方案

  grep file foo |而读线;做回声$行|日期％s。％N;完成
  

在脚本中可读性更强：

  grep file foo |而读行
做
 echo$ line|日期％s。％N 
完成
  

对于每一行输入， read 会将值放入变量 $ line 中，并且同时语句将在 do 和 done 之间执行循环体。由于该值现在是一个变量，而不是标准输入，因此我使用 echo 将其重新转换为标准输入，但是您可以只执行日期％ s。％N$ line，假设日期是这样的。

避免在`grep中使用文件foo` 类似，因为对于总是在空格上出现断裂，这对于读取文件列表来说是一场噩梦：

  find。 -iname* blah * .dat|同时读取文件名; do .... 
  

会因为而失败。

How to grep in one file and execute for every match a command?

File:

foo
bar
42
foo
bar

I want to execute to execute for example date for every match on foo.

Following try doesn't work:

grep file foo | date %s.%N

How to do that?

解决方案

grep file foo | while read line ; do echo "$line" | date %s.%N ; done

More readably in a script:

grep file foo | while read line
do
    echo "$line" | date %s.%N
done

For each line of input, read will put the value into the variable $line, and the while statement will execute the loop body between do and done. Since the value is now in a variable and not stdin, I've used echo to push it back into stdin, but you could just do date %s.%N "$line", assuming date works that way.

Avoid using for line in `grep file foo` which is similar, because for always breaks on spaces and this becomes a nightmare for reading lists of files:

 find . -iname "*blah*.dat" | while read filename; do ....

would fail with for.

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