The Bash history can get deleted just by deleting the file which contains. How can I protect the history from being cleared / deleted?
What you ask can be done with ...
sudo chattr +a ~$USER/.bash_history sudo chattr +i ~$USER/.profile
This will set the "append only" for
.bash_history and "immutable bit" for
.profile and even root can not delete or truncate the file unless that bit is removed. The 2nd command prevents the user from editing the settings for
Next put this in
# #Prevent unset of histfile, /etc/profile HISTFILE=~/.bash_history HISTSIZE=10000 HISTFILESIZE=999999 # Don't let the users enter commands that are ignored# in the history file HISTIGNORE="" HISTCONTROL="" readonly HISTFILE readonly HISTSIZE readonly HISTFILESIZE readonly HISTIGNORE readonly HISTCONTROL export HISTFILE HISTSIZE HISTFILESIZE HISTIGNORE HISTCONTROL
That will lock down most simple actions a user could make to mess this up. But it wont stop the more experienced users ...
- a user can simply switch to another shell and you wont see anything register.
- anyone with the admin password or any process with
CAP_LINUX_IMMUTABLEcapability can remove the immutable bit
- commands that start with a space by default are not stored in history.
- you can not stop a
kill -9 $$. That command will prevent writing to history.
So what you ask is rather pointless. If you do not trust your users do not let them on your system.
If this question was created to tract actions by hackers... you can totally forget about this; they are not likely to use bash when they are on your system and this history only works with bash.
This is not the answer you were looking for, but what you really want is linux's audit system, not bash. The audit system is designed expressly for things like this, whereas shell history is a convenience feature and there are many ways to modify it or simply not use it, as stated in many answers above.
You cannot protect the
.bash_history file from getting deleted. If you make its permission bits read-only, bash will fail to write in it.
However, you can create an alias for
rm in your
~/.bashrc so that, every time you want to delete something, it will ask you
Put this line in your
alias rm="rm -i"
Also make sure it is only you who can read/write from/to that file.
chmod 600 ~/.bashrc
should do the job.
Not a protection against the deletion itself, but a way to keep a backup is to keep the ~/.bash_history in Dropbox and symlink to it.
I guess there are other backup software to continuously back up as well in different ways.