如何在Linux中的变量存储的命令？ [英] How to store a command in a variable in Linux?

问题描述

我想用来存储一个命令在一个变量后期使用（不是命令的输出，但命令本身）

I would like to store a command to use at a later period in a variable (not the output of the command, but the command itself)

我有一个简单的脚本如下：

I have a simple script as follows:

command="ls";
echo "Command: $command"; #Output is: Command: ls

b=`$command`;
echo $b; #Output is: public_html REV test... (command worked successfully)

然而，当我尝试一些更复杂的，它失败。例如，如果我做

However, when I try something a bit more complicated, it fails. For example, if I make

command="ls | grep -c '^'";

输出是：

Command: ls | grep -c '^'
ls: cannot access |: No such file or directory
ls: cannot access grep: No such file or directory
ls: cannot access '^': No such file or directory

任何想法，我怎么能存储这样的命令（管道/多个命令），以供日后使用变量？

Any idea how I could store such a command (with pipes/multiple commands) in a variable for later use?

推荐答案

使用eval。

x="ls | wc"
eval $x
y=`eval $x`
echo $y

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