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Linux 命令符号 !ls 含义

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Linux 命令符号 !ls 含义

命令中的 ! 是什么意思？例如 ls 命令，输入 !ls 后输出什么？

答案1

它的意思是运行历史列表中以 开头的最后一个命令，ls正如我所指出的那样。如果您最后运行的命令是 ，lsb_release那么它将被运行。如果您只运行该命令，ls它将为您提供目录列表。它运行以您指定的任何内容开头的最后一个或最近的命令。

如果您history在系统上运行，您将看到您运行过的所有命令。如果您想要从历史记录中运行特定命令，则就像运行我之前的命令!#一样。!1990cd

历史输出示例：

 1990  cd
 1991  sync
 1992  ssh [email protected]
 1993  sync
 1994  sync
 1995  sudo apt autoremove
 1996  reboot
 1997  sudo apt remove nvidia-driver-430
 1998  sudo apt install nvidia-driver-435
 1999  sudo apt autoremove
 2000  reboot
 2001  ./intrepid_check.bsh 
 2002  ssh intrepid
 2003  ls -al
 2004  ls
 2005  ls -al
 2006  history
terrance@terrance-ubuntu:~$

如果我想运行ssh列表中的最后一个命令，我会输入

!ssh

例子：

terrance@terrance-ubuntu:~$ !ssh
ssh intrepid
Welcome to Ubuntu 18.04.3 LTS (GNU/Linux 5.0.0-29-generic x86_64)

 * Documentation:  https://help.ubuntu.com
 * Management:     https://landscape.canonical.com
 * Support:        https://ubuntu.com/advantage

 * Congrats to the Kubernetes community on 1.16 beta 1! Now available
   in MicroK8s for evaluation and testing, with upgrades to RC and GA

     snap info microk8s

 * Canonical Livepatch is enabled.
   - All available patches applied.

0 packages can be updated.
0 updates are security updates.

Your Hardware Enablement Stack (HWE) is supported until April 2023.
You have mail.
Last login: Wed Sep 25 21:38:55 2019 from 10.0.0.100
-------------------------------------------------------------- 09/25/19 21:43:36
terrance@Intrepid:~$

希望这可以帮助！

答案2

阅读man bash。其中部分内容如下：

Event Designators
   An  event  designator  is a reference to a command line entry in the history list.  Unless
   the reference is absolute, events are relative to the  current  position  in  the  history
   list.

   !      Start  a  history  substitution, except when followed by a blank, newline, carriage
          return, = or ( (when the extglob shell option is enabled using the shopt builtin).
   !n     Refer to command line n.
   !-n    Refer to the current command minus n.
   !!     Refer to the previous command.  This is a synonym for `!-1'.
   !string
          Refer to the most recent command preceding the current position in the history list
          starting with string.
   !?string[?]
          Refer to the most recent command preceding the current position in the history list
          containing string.  The trailing ? may be omitted if string is followed immediately
          by a newline.
   ^string1^string2^
          Quick  substitution.   Repeat the previous command, replacing string1 with string2.
          Equivalent to ``!!:s/string1/string2/'' (see Modifiers below).
   !#     The entire command line typed so far.

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