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@andkirby
Last active August 19, 2020 11:07
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Reset time on ssh login in a Unix system
########################################
# Reset time on login #
########################################
# you may try to use system last logged time: `last ${USER} -n1 | head -1 | awk '{print $4" "$5" "$6" "$7}'`
time_sync_command='sudo ntpdate -s time.nist.gov'
# max time not logged value
not_logged_max_time_h=6
if ! [[ -f ~/.last_login_time ]]; then
date > ~/.last_login_time
fi
# calculation
((last_time=$(date --date="$(cat ~/.last_login_time)" +%s), \
current_time=$(date --date="$(date)" +%s), \
tdiff=current_time-last_time, last_login_diff=tdiff/3600))
if [[ ${last_login_diff} -ge ${not_logged_max_time_h} ]]; then
echo 'Time sync (.bashrc)...'
${time_sync_command}
fi
date > ~/.last_login_time
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andkirby commented Aug 19, 2020

For vagrant, please update Vagrantfile with following:

Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|
...
  # Sync up time with servers
  config.vm.provision(
    :shell,
    :inline => 'sudo ntpdate -s time.nist.gov && echo "VM time is up-to-date." || echo "ERROR: Cannot sync time." > /dev/stderr',
    run:    'always')
...
end

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