When we run the "history" command it only gives you command along with the line numbers. Sometimes it’s useful to have a time stamp attached to each command to build a clearer picture.
Below example shows the history command output without timestamps.
To enable the timestamps in history command we have to set “HISTTIMEFORMAT “ environment variable.
# export HISTTIMEFORMAT="%F %T "
To permanently set this variable use .bashrc file
Below Output shows timestamps in history commands.