DOKK / manpages / debian 10 / undertime / undertime.1.en
UNDERTIME(1) General Commands Manual UNDERTIME(1)

undertime - pick a meeting time

undertime [--start HOUR] [--end HOUR] [--date WHEN] [--colors|--no-colors] [--default-zone--no-default-zone] [--config FILE ] [timezones]
undertime --print-zones

undertime is a program that allows you to quickly pick a meeting time across multiple timezones for conference calls or other coordinated events. It shows all times of a given day for all the timezones selected, in a table that aligns the time so a line shows simultaneous times across all timezones. This takes into account daylight savings and other peculiarities (provided that the local timezone database is up to date) so you can also schedule meetings in the future as well.

An educated guess is made to find the relevant timezones: the local timezone is first guessed and added to the list, then the arguments on the commandline are looked up in the internal timezone database. Spaces in arguments are replaced by underscores and all-caps versions of lowercase strings are tried as well. When failing to match a provided timezone against the internal list, a warning is emitted. A complete list of timezones is shown when the --print-zones commandline option is provided.

Colors are used to highlight the "work hours" where possible meeting times could overlap and the current time is marked in bold. Colors are replaced by an underscore suffix and the current time by a star if colors are disabled. You can change those work hours with the --start and --end flags. Because daylight savings may actually change time, you can also use the --date time to pick an arbitrary time for the meeting, using natural language (as parsed by the parsedatetime library). The current time is also shown, in bold.

start of working day, in hours
end of working day, in hours
target date for the meeting, supports arbitrary dates like "in two weeks"
show colors. enabled by default if output is a terminal.
show current timezone first
show valid timezones and exit
load YAML config FILE as defaults.
Show summary of options and defaults

Default timezone.
If this environment variable is defined, no color will be shown unless the --colors flag is passed. Comforming to

~/.config/undertime.yml $XDG_CONFIG_DIR/undertime.yml
The configuration file loaded by default, if present. The configuration file is formatted as a YAML dictionary, where keys are the long option names (without dashes) and the values are their values. Comments start with the # character. Options provided as arguments override the defaults set in the configuration file, particularly timezones. For example, this means timezones specified in the configuration file are ignored ignored when also specified as arguments. The --config parameter allows you to load another configuration file, on top of the default one, using the same logic, allowing you to have multiple "presets".

Display possible meeting times for three major cities.
Show a longer work day in march 2014.

timezones: [US/Central, US/Pacific, Europe/Paris]
    
start: 10
end: 18
    
colors: false
    

tzselect(8) tzfile(5)

2018