Remove a certain line from Bash history file

Question

How can I remove a certain line from history's database?

Answer 1

You need to log out and back in or run history -a so the current history is committed to disk.

Then just edit the file ~/.bash_history.

Answer 2

You can achieve removal from the history file using the commandline in two steps:

1. Typing history -d <line_number> deletes a specified line from the history in memory.
2. Typing history -w writes the current in-memory history to the ~/.bash_history file.

The two steps together remove the line permanently from the in-memory history and from the .bash_history file as well.

Answer 3

To prevent a command from being added to the history in the first place, make sure that the environment variable HISTCONTROL contains among its colon-separated values the value ignorespace, for example (add e.g. to .bashrc):

$ export HISTCONTROL=ignorespace

This will prevent any command with a leading space from being added to the history. You can then clear the history completely by running

$  history -c -w
  ^-- additional space character

Answer 4

First of all, if the command you're about to issue is sensitive, unsafe, or you just don't need it cluttering up your history, it is best/quickest to just prevent it from entering the history in the first place. Make sure that $HISTCONTROL contains ignorespace:

(bash)$ echo $HISTCONTROL
ignoredups:ignorespace

Then proceed any command you don't want in your history with a space:

(bash)$  sensitive-cmd-with --password 82cf7dfe
(bash)$  rm -r... # One-off recursive remove; mustn't be accidentally repeated!

If you accidentally put an unwanted command into history, providing that your bash session is still open, the command hasn't yet touched the disk. To delete the previous command in history, issue:

(bash)$  history -d $((HISTCMD-1))

Note the leading space; this command requires ignorespace, otherwise it'll just delete itself!

If you want to delete the last few commands, find the last and first history number:

(bash)$  history 5
  598  ok
  599  sensitive
  600  unsafe
  601  doesn\'t-work
  602  otherwise-unwanted

In this case 602 and 599. Then issue:

(bash)$  for i in {602..599}; do history -d $i; done

(Without ignorespace, it would be 603..599.)

If you don't want any history from your current session to hit the disk, exit using:

(bash)$ kill -9 $$

The approach so far is to not even let sensitive history items be written to disk for extra security, because in theory data deleted from non-volatile media can still be recovered.

If, however, the command(s) you wish to remove are from a previous session, they will have already been appended to the $HISTFILE on exit. Manipulating the history with the above commands will still only append the remaining new items to the $HISTFILE, on exit. To overwrite the $HISTFILE with the current session's view of the entire history, right now, issue:

(bash)$  history -w

Of course for history items already on disk, the alternative to editing the history with history -d commands then issuing history -w, is to edit the $HISTFILE with a text editor.

Answer 5

Several techniques:

Prevent sensitive information from being stored in the history file

If you've entered some password on a command line, then realize that all commands are logged, you could either:

1. Force exit the current session without saving history:

    kill -9 $$
   

   This will drop all current history.

2. Type ↑ (up arrow) in the open bash session until the sensitive information is shown, then use line editing keystrokes like Ctrl+W to delete the sensitive info, and then ↓ (down arrow) until a new empty line is prompted, before typing Enter.

Delete sensitive information from the history file

If you realize that sensitive information is already stored, and you want to delete it, but not your entire history:

A simple sed command could do the job:

sed -e '/SeNsItIvE InFo/d' -i .bash_history

but, as you type this, you create another history line containing the search pattern (sensitive info) you are trying to delete. So you could:

sed -e "/$(head -n1)/d" -i .bash_history

This will run head -n1 with input from the terminal. It will appear that your terminal is hung (there won't be a prompt); just type the information that you want to delete from the file. This is a trick to let you enter (part of) a command without actually typing it into the command line, thus making it ineligible for inclusion in the history record. Then sed will use the text that you typed to search .bash_history and delete all lines containing the sensitive info. Note: if your sensitive information pattern contains slash(es), you must escape them with backslashes, or else change the sed command to use this syntax to specify a delimiter that does not appear in the pattern:

sed -e "\|$(head -n1)|d" -i .bash_history

Another way could be to delete only the sensitive info, but keep the commands that contain the information. For this, you could simply replace sensitive info with substitute text of your choice:

sed -e "s/$(head -n1)/Santa Claus/g" -i .bash_history.

Delete sensitive information from any file in a specific tree

Finally, to be sure that this won't stay in another forgotten file:

SENSITIVEINFO="$(head -n1)"
find . -type f -print0 | xargs -0 grep -l "$SENSITIVEINFO"

will list all concerned files.

find . -type f -print0 |
    xargs -0 grep -l "$SENSITIVEINFO" |
    tr \\n \\0 |
    xargs -0 sed -e "s/$SENSITIVEINFO/Santa Claus/g" -i

will replace all occurrences of sensitive info in all files in the directory tree rooted at .. Note: even though this command uses xargs -0, it will not handle files with newlines in their names.

Answer 6

Locate the line you want to delete by pressing ↑ (up arrow) until it appears, then press Ctrl+U. That should remove the line.

If you use the history command, you can see the line has been substituted with an asterisk.

Answer 7

If you need to remove several lines at the same time I normally use this:

history | grep <string> | cut -d ' ' -f 3 | awk '{print "history -d " $1}'

If you need to remove the last command you can use:

history -d $((HISTCMD-2))

Answer 8

If you need to remove a range of lines from history, the following bash function could save you some time:

function histdel() {
    [ $# -eq 1 ] && history -d "$1" && history -w
    if [ $# -eq 2 -a "$1" -le "$2" ]; then
        for n in `seq "$2" "$1"`; do
            history -d "$n"
        done
        history -w
    fi
}

Function should be typically added to $HOME/.bashrc. To use the function imediatelly, you will need to have the file read again by your running shell (. $HOME/.bashrc). Then to delete e.g. commands 200-210 from history:

$ histdel 200 210

(Note: This question is among the top search results if you search for deleting a range of commands from bash history. So, while the above is more than what the question asks, it could be useful for some readers.)

Answer 9

history | sed -i 59d

59 is the line number. Cannot be anything sweeter than this :)

Answer 10

Just try these,

$ history

this will display the id of the history and the command, e.g.

.
.
211 ls
212 javac Welcome.java
213 java welcome
.
.

use,

$ history -d 211

Here 211 is the id of the history. Now check this using

$ history

.
.
211 javac Welcome.java
212 java welcome
.
.

Answer 11

I know it's been a long time since this question has been asked and answered but I'll show you my method for cleaning my history file and logging out at the same time.

I run : history -w && nano "${HISTFILE}" && history -c && exit

What it does is simple:

1. history -w : writes cached history inside "${HISTFILE}"
2. nano "${HISTFILE}" : allow me to edit "${HISTFILE}" You could use a sed script or whatever your want to clean your "${HISTFILE}"
3. history -c : clear cached history so this last command is not appended.
4. exit : log me out appending cached history... but it is empty ;)

After that command, you'll be logged out with a clean history file. Log in to check your history ;)

I hope this will help someone.

Answer 12

You could also edit the history file directly, eg nano .bash_history if you are in the bash shell?