Linux

Hi,
Just wanted to know if anyone else has noted that the time-stamp in the history is all out of whack.
I've Ubuntu, all patched, and when I ran history, it showed me commands that I ran few weeks ago with today's date. Is this normal?
Here is a snippet:

Code:

....
   85  2010-06-09 09:03:31 ls
   86  2010-06-09 09:03:31 cd ..
   87  2010-06-09 09:03:31 ls
   88  2010-06-09 09:03:31 ls -l
   89  2010-06-09 09:03:31 df -h
   90  2010-06-09 09:03:31 ls
   91  2010-06-09 09:03:31 screen 
....

Now I know ran the above ls and cd a few days ago, but it's showing today's date. In fact, most of them are like that.
Suggestions?

Nitin

What shell are you using? bash, at least on my ubuntu machines, doesn't seem to have any datestamps at all, although the man page for history(3) does describe datestamps in the structures used for the api.

What file are you quoting above?

I'm using bash.
And the above output is from regular history command.

I also use screen though, don't know how the history merges commands between different terminals.

Thanks,
Nitin

Hmmm. On the Ubuntu machines I have access to, which are admittedly not the most recent releases, the history command doesn't show dates in it's output. The .bash_history file also doesn't have datestamps on my boxes.

Could you run "which history" and "whereis history" and send the results?

The history and fc are bash builin commands, so when I did which history I got nothing.

Code:

root:~$ which history
root:~$ whereis history
history: /usr/share/man/man3/history.3readline.gz
root:~$

I'm getting dates because of this envar:

Code:

HISTTIMEFORMAT=%F %T

I could unset it and then I will see the usual history with number and command next to it. I'm leaning towards this being some kind of a bug!

Yeah, I tested it with manipulating HISTTIMEFORMAT, and it shows same date and time for all the commands. BTW, the time is synced daily on my Linux box, so it can't be because of that.

Thanks,
Nitin

OK, I think I figured this out.

If you don't have HISTTIMEFORMAT set, but do have a history file, and then set HISTTIMEFORMAT, your history will all show the same time.

If you then set HISTTIMEFORMAT in .bashrc, say, so that it's persistent across sessions, log out, log back in, run some commands, and then run history, you'll see the timestamps being updated correctly.

If, as I wonder if you did, you didn't have HISTTIMEFORMAT set at some time in the past, then set it and expected your previous history entries to have the correct datestamp, it won't work. Essentially, having this variable set acts as a switch to have history _start_ saving datestamp data - if it wasn't set, then it won't save it.

Does that make sense? I may not be expressing this well.

You are right about
I just tested added HISTTIMEFORMAT in .bashrc of a Redhat server. All my previous commands had time-stamp of the time I ran history after adding HISTTIMEFORMAT. But any new commands had different timestamps. Here is the thing, I didn't set the HISTTIMEFORMAT in Ubuntu. I just re-checked the .bashrc, it already had this:

Code:

export HISTTIMEFORMAT="%F %T "

I really didn't pay attention to history till just now. Well, the current Ubuntu machine has been running for almost a year, and I've not changed any bash profiles or .bashrc. In a nutshell, the time format envar is not very trustworthy, and is confusing at best. I almost had a heart attack thinking someone was doing something on my server.
It's all good now.

Thanks,

Nitin