bash - How can I see a timestamp for when a command was executed using history?

07
2014-07
  • Jonathan Day

    I'd like to check at what time/date a command in bash history was executed. Is this possible?

    • Answers
  • Siim K

    It is possible. The help history command says:

    If the $HISTTIMEFORMAT variable is set and not null, its value is used as a format string for strftime(3) to print the time stamp associated with each displayed history entry. No time stamps are printed otherwise

    I set the variable for my user like this (on Ubuntu):

    echo 'export HISTTIMEFORMAT="%d.%m.%y %T "' >> ~/.bashrc

    If you want it globally then add the line to /etc/bash.bashrc:

    echo 'export HISTTIMEFORMAT="%d.%m.%y %T "' >> /etc/bash.bashrc

    See man strftime for all possible formatting options

    The ouput of history on my box:

      ...
  132  05.05.11 10:45:11 ls
  133  05.05.11 10:45:14 cd ..
  134  05.05.11 10:45:17 history

    P.S. When you set the variable the first time then the entire history will get the time stamp of the moment the variable was set.


    • Related Question

    command line - How can I see Bash history from more than one terminal session in Ubuntu?
  • Jonas

    Possible Duplicate:
    Can history files be unified in bash?

    I use Ubuntu Server 9.10 and I would like to be able to see my bash history for more than one terminal sessions. I.e. my last 200 commands or so, even if I have been logged out in between.

    When I use the history I just see all commands from my actual terminal session. How can I see more command history from Bash? Is there any specific settings for bash that I should change from the default values in Ubuntu?

    I don't have a ~/.bash_history file. But I have an ~/.bashrc with HISTCONTROL=$HISTCONTROL${HISTCONTROL+,}ignoredups and HISTCONTROL=ignoreboth

    echo $HISTFILE
/home/sanoj/.bash_history
echo $HISTSIZE
500
echo $HISTFILESIZE
500
echo $HISTCONTROL
ignoreboth

    UPDATE: I am now trying Ubuntu Server 10.10 in VirtualBox. If I just turn off VirtualBox without the shutdown command, then next time when I boot, the commands from the last session is not saved in the history file.

    The commands are only saved if I shutdown the machine with the shutdown command. E.g. shutdown -P 0.

    This must be the reason to my problem. So I have to figure out how to save the command-history more often. E.g. after each command.


    • Related Answers
  • Dennis Williamson

    You can use

    history -a

    to immediately append the in-memory history to the history file. One terminal session can't see another's unless this is done or the other is exited.

    You can use

    history 200 | less

    to see that number of entries.

    In addition to HISTSIZE see the entry in the Bash man page concerning HISTFILESIZE.

  • Benjamin Bannier

    Once you log out the history gets appended to the file ~/.bash_history. Have a look in there.

    By default it will remember your last 500 commands. If you want to save more set the variable HISTSIZE in ~/.bashrc.

    I also do add ignoredups to HISTCONTROL (with HISTCONTROL=$HISTCONTROL:ignoredup). This makes duplicate consecutive commands to be save only once.

    Have a look at man 1 bash for what else you can tune about the history.

  • Ignacio Vazquez-Abrams

    bash history is usually loaded when the shell begins running, and is saved when it is exited normally. You can use history -a and history -n to override this, but not automatically unless you abuse $PROMPT_COMMAND or something similar.

  • Zac Thompson

    Sanoj, this really should "just work"; I don't think there is supposed to be anything special you need to do to enable this. It sounds like something is interfering with the normal course of events.

    I would look in /etc/profile, /etc/bashrc (or perhaps /etc/bash.bashrc according to some sources), ~/.bash_profile, ~/.bashrc, ~/.bash_login, ~/.bash_logout, to see if there is anything that might be affecting the history (perhaps grep -i hist on each of the above files).

    ... In particular I wonder if you have something in ~/.bash_logout that removes the file.

    Alternatively, is it possible that something is overriding the $HOME variable?