History clear all linux

How do I clear the terminal History?

I am using Linux Mint 17.1 Rebecca for about 2 days and accidentally typed my password into the terminal which is now displayed in the history list of commands I have previously typed. I want to clear the terminal history completely. I have tried using the following commands in the terminal which I thought would clear the history forever but they do not:

history -c reset tput reset 

The above commands «will» clear the history from the terminal but when I exit and bring up a new one all my previous history is still there and can all be listed again using the — history command and also by pressing the UP arrow on my keyboard. I do not want this to happen until I have totally cleared my history, then I want to continue using it. How can I clear my terminal history completely — forever and start fresh? Please Note: I do not want to exit the terminal without saving history just clear it forever in this one instance.

@jasonwryan That alone wouldn’t solve the problem since the sed command would end up in the shell history.

I tried using the code from @jasonwryan but I got: sed: -e expression #1, char 0: no previous regular expression which I think I know why and that lead me to come up with this from a search and some messing around: cat /dev/null > ~/.bash_history && history -c && exit

7 Answers 7

reset or tput reset only does things to the terminal. The history is entirely managed by the shell, which remains unaffected.

history -c clears your history in the current shell. That’s enough (but overkill) if you’ve just typed your password and haven’t exited that shell or saved its history explicitly.

When you exit bash, the history is saved to the history file, which by default is .bash_history in your home directory. More precisely, the history created during the current session is appended to the file; entries that are already present are unaffected. To overwrite the history file with the current shell’s history, run history -w .

Instead of removing all your history entries, you can open .bash_history in an editor and remove the lines you don’t want to keep. You can also do that inside bash, less conveniently, by using history to display all the entries, then history -d to delete the entries you don’t want, and finally history -w to save.

Note that if you have multiple running bash instances that have read the password, each of them might save it again. Before definitively purging the password from the history file, make sure that it is purged from all running shell instances.

Note that even after you’ve edited the history file, it’s possible that your password is still present somewhere on the disk from an earlier version of the file. It can’t be retrieved through the filesystem anymore, but it might still be possible (but probably not easy) to find it by accessing the disk directly. If you use this password elsewhere and your disk gets stolen (or someone gets access to the disk), this could be a problem.

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How to Clear BASH Command Line History in Linux

The bash history keeps a record of all commands executed by a user on the Linux command line. This allows you to easily run previously executed commands by using the “up arrow” or “down arrow” keys to scroll through the command history file.

In this article, we will show you two simple ways to clear your command-line history on a Linux system.

The major reason for removing command-line history from the Linux terminal is to prevent another user, who could be using the same account.

For instance if you have typed a command that contained a password in plain-text and you don’t want another system user or an attacker to see this password, you need to delete or clear the history file.

Take a look at the command below, here the user aaronkilik has typed the database server password on the command line.

If you look into th bash history file towards the end, you will see the password typed above in there.

The bash_history file is normally located in a user’s home directory /home/username/.bash_history.

$ ls -l /home/aaronkilik/.bash_history

To remove a single line from the history file, use the -d option. For example, if you want to clear a command where you entered clear-text password as in the scenario above, find the line number in the history file and run this command.

To delete or clear all the entries from bash history, use the history command below with the -c option.

Alternatively, you can use the command below to delete history of all last executed commands permanently in the file.

$ cat /dev/null > ~/.bash_history

Note: A normal user can only view his/her own command history, but the root user can view the command history of all other users on the system.

You can learn more about the bash history file and useful history commands here: The Power of Linux “History Command” in Bash Shell.

Always remember that all commands you run are recorded in a history file, so do not type plain-text passwords on the command line. If you have questions or thoughts to share with us, make use of the feedback form below.

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How to clear command history in Linux

The bash history stores the records of all terminal commands which are executed by a user on the command-line Linux system. Using the history feature, you can easily locate the previously executed commands on your Linux system through the arrow keys navigation.

Why should we remove the Linux Command line History?

Most of the time, we don’t want to reveal the terminal history of other users on your Linux system. For example, if you are giving classes to your students on a Lab computer and you might have taught some harmful commands and are not recommended to use on our system. But most of the students don’t have an idea about the side effects of these critical commands. A curious student may search about the command-line history and test them to check the working of each command. It may crash your system many times. However, you can repair or re-install your system in a quick way. But, it is not a good practice. So, in this case, we want to prefer to clear the command line history after working on it. Especially when you have shared access with your friends or colleagues. We have just elaborated it with just a simple example; there could be other problems through which you want to clear the Linux command line history. In this article, we will give you a demo of how you can clear the command line history in the Linux system.

We have executed all the commands on Ubuntu 20.04 terminal application in this article. Therefore, it is necessary to open the terminal window on your system. Click on the ‘Activities’ located at the left corner on your system’s desktop, and then using the application search bar, you will search the ‘terminal’ keyword. After completing the search, click on the terminal icon and launch it.

Removing the Linux Command line history

If you want to view the history of your terminal command then, type the following command on the terminal:

Normally, the command line history stores in a file named ‘bash_history’. This file you may locate in a particular user’s home directory /home/username/.bash_history. Execute the below-given command to locate the bash_history file:

Note: A root user can observe the command history of all user’s on your system. But, the standard user can only view their own command line history.

Remove a Line from the bash history

If you want to remove just a single line from the bash history file, then you can use the -d option with history command and enter the targeted line number, which you want to remove.

For example, we want to clear a command that contains your password where you have entered a password in a plain text; you can easily find the line number in the history file and clear it by executing the following command:

Remove or Clear all commands from the bash history

You can also clear or delete all entries from the bash history file. So, use the option -c with the history command. You can run the following command on the terminal to clear or delete the all bash history:

Alternatively, by running the following command, you can remove or delete all history of last executed commands in the bash history file permanently.

Conclusion

In this article, we have presented a better understanding of the history command and why we need to clear it. From the above all mentioned command, I hope now can clear the history of your system easily. But, always remember that what you perform on the terminal all commands recorded in a bash history file, so it is recommended that you never use passwords in a plain-text format on the Linux command line. If you have any queries and thoughts related to this article then, please share your ideas with us.

About the author

Karim Buzdar

Karim Buzdar holds a degree in telecommunication engineering and holds several sysadmin certifications. As an IT engineer and technical author, he writes for various web sites. He blogs at LinuxWays.

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How to Clear Command History in Linux?

In Linux, the history command is a utility that allows you to view a list of previously entered commands in the terminal. It is a useful utility to overlook the commands and then reuse them easily.

While using too many terminal commands, Linux administrators recommend clearing the terminal’s history regularly. In this post, we will list the possible ways to clear the command history in Linux.

• Why Do You Need to Clear Command History?
• Display Current History in Linux
• Clear Current Session’s Command History
• Clear the Command History All Terminal Sessions
• Clear the History from Previous Sessions

Let’s start the article with the importance of clear command history.

Why Do You Need to Clear Command History?

There are several reasons you might want to clear the command history in Linux:

• Privacy: The command history is stored in a file on your computer, and it can be accessed by anyone who has access to that file. Clearing the command history can help to protect your privacy by preventing others from seeing the commands you have typed.
• Security: If you have typed sensitive information, such as passwords or confidential data, into the terminal, clearing the command history can help to protect that information from being accessed by others.
• Convenience: The command history can become cluttered over time, making it difficult to find specific commands. Clearing the command history can help clean up the list and make it easier to find the commands you need.
• Debugging: If you are having problems with your terminal or with a specific command, clearing the command history can help to resolve those issues.

How to Display Commands History in Linux?

To display the current history in Linux, the “history” command is utilized in the terminal below:

The output displays all the previous history in this terminal.

How to Clear the Command History of the Current Session?

For clearing the command history in Linux, utilize the history command followed by the “-c” option. This will clear the current session’s command history.

To clear the command history, you can use the following command:

Note that this will only clear the command history for the current terminal session.

How to Clear the Command History of All Terminal Sessions?

The “.bash_history” file contains the commands run on all terminal sessions. To clear the command history for all terminal sessions, run the below script:

$ cat /dev/null > ~/.bash_history

This will overwrite the “bash_history” file with an empty file.

How to Clear the History From Previous Sessions?

Use the history command with the -w option for writing the current history to the .bash_history file and overwrite it with the current session’s commands:

This can be useful if you want to preserve the current session’s command history but clear the history from previous sessions.

That is how clear the command history

Conclusion

Linux offers the “history” utility with the “-c” option to clear the command history. It clears the current sessions. Additionally, the “-w” option is helpful to clear all previous sessions of command history by maintaining the current session history. It is a useful way to manage and maintain your terminal environment. This article has demonstrated all multiple methods to clear the command history in Linux.

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