Ubuntu – How to uniqely record every new command I use, and possibly timestamp it

bashbashrccommand line

I've been on Linux for more than 6 months now but never went too much into the CLI (command-line interface or terminal or shell)

Now as I ask questions here, get answers, or help from other sites, I learn new commands…

How can I can store every new command in a text file? Only new/unique commands, not repetitions of the same command.

Here's an example:

In the terminal, I enter the commands like this-

$  command1
$  command2
$  command3
$  command4
$  command1

Now, these commands should get saved in a text file say commandrec like this

command1
command2
command3
command4

NOTE: The last command in the terminal which was again command1 is not recorded/saved again in the text file.

And the next time I open the terminal, and enter a new command command 5, it should get appended to the list in commandrec

(but if the command was used earlier on some other date, it should still be ignored. For example, command 1 entered again along with command 5 on a new day/time but command1 not recorded as already used)

The commandrec file will be looking something like this

31/05/12 12:00:00
command1
command2
command3
command4
01/06/12 13:00:00
command 5

(the time and date thing would be great if possible, but okay even if that isn't there)

This way, I can have a record of all commands used by me to date.

How can this be done?

Best Answer

How to successfully experiment with changing these settings in `.bashrc`

Before experimenting: Save your current .bash_history to another file with cp.
While experimenting with what works: rm ~/.bash_history after you change .bashrc with history control parameters, otherwise the combo of old and new entries may give you weird results.
- e.g., all entries before timestamps were enabled will show the same current date/time!
Once you find something that works, DO NOT rm any more!!
Note also that any changes to .bashrc are reflected only when you exit and then instantiate a new terminal/shell.

Increasing history size and eliminating duplicates

Add these lines to your ~/.bashrc:

export HISTCONTROL=erasedups
export HISTSIZE=10000

History size is set to 10000, duplicates are automatically eliminated so it's plenty of space :)

Timestamping

Time can be set easily by adding another line of the form export HISTTIMEFORMAT="%F %T", this will display the time/date before each line when using history
- Example:
```
izx@preciseunity:~$ history
1  2012-06-01 07:16:22 rm ~/.bash_history
2  2012-06-01 07:16:23 exit
3  2012-06-01 07:16:27 ls
4  2012-06-01 07:16:31 test
5  2012-06-01 07:16:34 ls /etc
6  2012-06-01 07:16:36 down
7  2012-06-01 07:16:37 up
8  2012-06-01 07:16:40 hustory
9  2012-06-01 07:16:48 history
```
- Note that because duplicates are eliminated, the time shown for a command is the latest (newest) time it was last executed.
- You can customize the HISTTIMEFORMAT to your choice/locale based on strftime

Related Solutions

Ubuntu – The program ‘sed’ is currently not installed. You can install it by typing [sed: not found]

Besides copying the binary from another machine and hoping it is the correct version, this can also be solved by using apt or apt-get to install the sed package and passing the --reinstall option so that the .deb file will be downloaded and installed even though Ubuntu's package manager thinks it is already present.

sudo apt install --reinstall sed

This works with apt-get instead of apt, too. It uninstalls and reinstalls the package in a single step. The situation in this problem is that the se package is already installed but the executable has been deleted, so reinstalling solves that. Without the --reinstall flag, the package manager assumes nothing has to be done, because the package is installed already.

You can run sudo apt update first if you want, though it will not typically be necessary in this case, unless you've modified your software sources without doing so. You can pass the --purge flag too if you want but it's unnecessary here, since that just causes conffiles for the package to be removed when it is uninstalled.

sed is a utility that programs are generally allowed to assume exists and to rely on themselves. As you noticed, the scripts that run when installing, removing, or upgrading software can use sed. That's the source of your specific error messages. In theory APT or dpkg could rely on it directly and be unable to reinstall it. In practice, this does not appear to happen, and I don't expect it to. I've tested this on Ubuntu 16.04 LTS.

I cannot think of any situation where replacing the binary fixes the problem but reinstalling neither works nor shows an error immediately (see comments on the post). Although I cannot be 100% sure that these instructions would work for you--because perhaps more was broken than documented in the question--they should generally work at least as reliably as manually replacing /bin/sed for others who experience this problem.

Editing .bashrc Messes Up Terminal Command History – How to Fix

I have no idea why (never really understood the escape codes), but adapting the other prompt seems to work:

PS1='\[\033[1;32m\][\W]\$ \[\033[00m\]'

Apparently, you need to enclose the escape sequences in \[...\], to tell bash not to count them while determining the prompt width. Therefore, both the above PS1 and the following would work equally well:

PS1='\[\e[1;32m\][\W]\$ \[\e[m\]'