How To Display Date And Time In History Command

https://www.2daygeek.com/display-date-time-linux-bash-history-command

We all are familiar with History command. It stores/keep all the commands executed by bash in terminal into .bash_history file, which will help us to recheck the previously executed commands by user for further investigation.
By default history command shows only the commands executed by users and it doesn’t print the date and time but it logs the time when you ran a command.
Whenever you run history command, it looks for an environment variable called HISTTIMEFORMAT, which tells how to format date & time with history command.
If the value is null or not set then it will shows default results like how most of the systems shows (Without date and time).
HISTTIMEFORMAT takes values from strftime (strftime – convert date and time to a string). When you have date and time in history command output, it might help you to track the issue easily.

• %T : Replaced by the time ( %H : %M : %S ).
• %F : Equivalent to %Y – %m – %d (the ISO 8601:2000 standard date format).

See below default history command output.

# history
    1  yum install -y mysql-server mysql-client
    2  service mysqld start
    3  sysdig proc.name=sshd
    4  sysdig -c topprocs_net
    5  sysdig proc.name=sshd
    6  sysdig proc.name=sshd | more
    7  sysdig fd.name=/var/log/auth.log | more
    8  sysdig fd.name=/var/log/mysqld.log
    9  sysdig -cl
   10  sysdig -i httplog
   11  sysdig -i proc_exec_time
   12  sysdig -i topprocs_cpu
   13  sysdig -c topprocs_cpu
   14  sysdig -c tracers_2_statsd
   15  sysdig -c topfiles_bytes
   16  sysdig -c topprocs_cpu
   17  sysdig -c topprocs_cpu "fd.name contains sshd"
   18  sysdig -c topprocs_cpu "proc.name contains sshd"
   19  csysdig
   20  sysdig -c topprocs_cpu
   21  rpm --import https://s3.amazonaws.com/download.draios.com/DRAIOS-GPG-KEY.public
   22  curl -s -o /etc/yum.repos.d/draios.repo http://download.draios.com/stable/rpm/draios.repo
   23  yum install -y epel-release
   24  yum update
   25  yum makecache
   26  yum -y install kernel-devel-$(uname -r)
   27  yum -y install sysdig
   28  sysdig
   29  yum install httpd mysql
   30  service httpd start

We can set this environment variable in three ways based on our requirements.

• Temporarily to current user
• Permanently to current/other user
• Permanently to all users

Note : Don’t forget to add space before the last single-quotes, otherwise the output would be messy.

Method-1 :

Run the following command to set HISTTIMEFORMAT variable temporarily to current user. This will go away after reboot.

# export HISTTIMEFORMAT='%F %T '

Method-2 :

Append following HISTTIMEFORMAT variable to .bashrc or .bash_profile file to make it permanent for every user.

# echo 'HISTTIMEFORMAT="%F %T "' >> ~/.bashrc
or
# echo 'HISTTIMEFORMAT="%F %T "' >> ~/.bash_profile

Run the following command to to effect the changes made to the file.

# source ~/.bashrc
or
# source ~/.bash_profile

Method-3 :

Append following HISTTIMEFORMAT variable to /etc/profile file to make it permanent to all users.

# echo 'HISTTIMEFORMAT="%F %T "' >> /etc/profile

Run the following command to to effect the changes made to the file.

# source /etc/profile

See the sample output.

# history
    1  2017-08-16 15:30:15 yum install -y mysql-server mysql-client
    2  2017-08-16 15:30:15 service mysqld start
    3  2017-08-16 15:30:15 sysdig proc.name=sshd
    4  2017-08-16 15:30:15 sysdig -c topprocs_net
    5  2017-08-16 15:30:15 sysdig proc.name=sshd
    6  2017-08-16 15:30:15 sysdig proc.name=sshd | more
    7  2017-08-16 15:30:15 sysdig fd.name=/var/log/auth.log | more
    8  2017-08-16 15:30:15 sysdig fd.name=/var/log/mysqld.log
    9  2017-08-16 15:30:15 sysdig -cl
   10  2017-08-16 15:30:15 sysdig -i httplog
   11  2017-08-16 15:30:15 sysdig -i proc_exec_time
   12  2017-08-16 15:30:15 sysdig -i topprocs_cpu
   13  2017-08-16 15:30:15 sysdig -c topprocs_cpu
   14  2017-08-16 15:30:15 sysdig -c tracers_2_statsd
   15  2017-08-16 15:30:15 sysdig -c topfiles_bytes
   16  2017-08-16 15:30:15 sysdig -c topprocs_cpu
   17  2017-08-16 15:30:15 sysdig -c topprocs_cpu "fd.name contains sshd"
   18  2017-08-16 15:30:15 sysdig -c topprocs_cpu "proc.name contains sshd"
   19  2017-08-16 15:30:15 csysdig
   20  2017-08-16 15:30:15 sysdig -c topprocs_cpu
   21  2017-08-16 15:30:15 rpm --import https://s3.amazonaws.com/download.draios.com/DRAIOS-GPG-KEY.public
   22  2017-08-16 15:30:15 curl -s -o /etc/yum.repos.d/draios.repo http://download.draios.com/stable/rpm/draios.repo
   23  2017-08-16 15:30:15 yum install -y epel-release
   24  2017-08-16 15:30:15 yum update
   25  2017-08-16 15:30:15 yum makecache
   26  2017-08-16 15:30:15 yum -y install kernel-devel-$(uname -r)
   27  2017-08-16 15:30:15 yum -y install sysdig
   28  2017-08-16 15:30:15 sysdig
   29  2017-08-16 15:30:15 yum install httpd mysql
   30  2017-08-16 15:30:15 service httpd start