How to log every single command executed from shell script

Question

I am trying to find a way to record every single command that is executed by any user on the system. Things that I have came across earlier.

1. It is possible to view shell commands executed from the terminal using ~/.bashrc_history file.

There is a catch here, It logs only those commands which were executed interactively from bash shell/terminal.

This solves one of my problems. But in addition to it, I would like to log those commands also which were executed as a part of the shell script.

Note: I don't have control over shell script. Therefore, adding verbose mode like

#!/bin/bash -xe

is not possible.

However, this can be assumed that I have root access as a system administrator.

Eg: I have another user that has access to the system. And he runs the following shell script using from his account.

 #./bin/sh nmap google.com

and run as "$ sh script.sh"

Now, What I want is "nmap google.com" command should be logged somewhere once this file is executed.

Thanks in advance. Even a small help is appreciated.

Edit: I would like to clarify that users are unaware that they are being monitored. So I need a solution something at system level(may be agent running with root). I cannot depend on user to log suspicious activity. Of-course everyone will avoid such tricks to put blame on someone else if they do something fishy or wrong

Answer 1

You can run the script in this way:

• execute bash (it will override the shebang)
• ts to prefix every lines
• logs both in terminal and files

bash -x script.sh |& ts | tee -a /tmp/$(date +%F).log

You may ask the other user to create an alias.

Edit: You may also add this into /etc/profile (sourced when users login)

exec > >(tee -a /tmp/$(date +%F).log)

Do it also for error output if needed. Keep it splited.

Answer 2

I am aware that you were asking for Bash and Shell scripting and tagged your question accordingly, but in respect to your requirements

• Record every single command that is executed by any user on the system
• Users are unaware that they are being monitored
• A solution something at system level

I am under the assumption that you are looking for Audit Logging .

So you may take advantage from articles like

• Log all commands run by Admins on production servers
• Log every command executed by a User