Install with:

1sudo apt install at

Enable the daemon service with:

1sudo systemctl enable --now atd

Then jobs can be specified with absolute time, such as:

1at 16:20

1at noon

1at midnight

1at teatime

Type in your command, e.g.:

1touch /tmp/$FILE.txt

The jobs can also be specified relative to the current time:

1at now …

Show system time:

1date

Show hardware time:

1sudo hwclock -r

Change system time to match hardware time:

1sudo hwclock --hctosys

Change hardware time to match system time:

1sudo hwclock --systohc

Manually set the hardware time to a specified date:

1sudo hwclock --set --date="8/25/19 13:30:00"

Normal Date

1date …

Cronie

The cronie program is also known as crond.

Install

1sudo apt search -n ^cron

Once installed, search for the service name, and start it.

1sudo systemctl list-unit-files | grep cron
2sudo systemctl enable --now $NAME

Usage

Show your current crontab:

1crontab -l

You can put this in a file and edit it:

1crontab -l …

Your locale tells the computer your location, preferred time-and-date format, standard language, papersize, et c. A list of supported locales is available at /usr/share/i18n/SUPPORTED

See a full list with:

1cat /usr/share/i18n/SUPPORTED

Take the first portion to generate full locale information for a region:

1 …

systemd

Set time to synchronize with an ntp server:

1timedatectl set-ntp true

This info stays in /usr/share/zoneinfo.

Local Time

Local time is kept in /etc/localtime.

According to Dave's LPIC guide, you can set the local time by making asymboling link from your timezone to /etc/localtime, as so:

1sudo ln -sf …

Summaries

Try:

1timew summary :yesterday

You can also use :week, :lastweek, :month, :quarter, :year, or a range such as:

1timew summary today to tomorrow
2timew today - tomorrow
32018-10-15T06:00 - 2018-10-17T06:00

Each of these can gain with the :ids tag.

Basics

1timew start
2timew stop
3timew continue
4timew summary …