tzconv: convert a date and time to several time zones at once

This Python package provides a small command-line utility to convert a YYYY-MM-DD HH:MM formatted date and time to several other time zones.

Installation

tzconv is available through PyPI:

$ python3 -m pip install tzconv

Alternatively, you can install it directly from the Codeberg Git repository:

$ git clone https://github.com/gn0/tzconv
$ python3 -m pip install --user ./tzconv

Usage

Basic usage

tzconv uses the time zone information available through your operating system, so time zones have to be specified accordingly:

$ tzconv \
    -f America/New_York \
    -t Pacific/Galapagos \
    -t America/Santa_Isabel \
    "2023-04-25 10:00"
EDT: 2023-04-25 10:00 (America/New_York)
-06: 2023-04-25 08:00 (Pacific/Galapagos)
PDT: 2023-04-25 07:00 (America/Santa_Isabel)
$

Time zone names can be shortened as long as they remain unique. Initials, prefixes, and abbreviations are all recognized:

$ tzconv \
    -f ny \
    -t gal \
    -t san_i \
    "2023-04-25 10:00"
EDT: 2023-04-25 10:00 (America/New_York)
-06: 2023-04-25 08:00 (Pacific/Galapagos)
PDT: 2023-04-25 07:00 (America/Santa_Isabel)
$

Available time zones can be listed with the --list-tz option (or -l for short):

$ tzconv -l am/n
The following time zones are available that match 'am/n':

  America/Nassau, America/New_York, America/Nipigon, America/Nome,
  America/Noronha, America/North_Dakota/Beulah, America/North_Dakota/Center,
  America/North_Dakota/New_Salem, America/Nuuk
$

Imputing the current date and the current time

If the date is omitted, today's date is imputed:

$ tzconv -f ny -t aa 10:00
EDT: 2023-04-20 10:00 (America/New_York)
EAT: 2023-04-20 17:00 (Africa/Addis_Ababa)
$

If the time is omitted, too, then tzconv imputes the current time:

$ tzconv -f ny -t aa
EDT: 2023-04-20 15:03 (America/New_York)
EAT: 2023-04-20 22:03 (Africa/Addis_Ababa)
$

Daylight savings

Daylight savings can complicate conversions. However, thanks to the Python standard library, tzconv is aware of changes to daylight savings, and it infers the correct offsets. For example, in March 2023, New York switched to daylight savings two weeks earlier than Budapest. Notice the switch from EST/CET to EDT/CET, and finally to EDT/CEST:

$ tzconv -f ny -t bud "2023-03-07 10:00"
EST: 2023-03-07 10:00 (America/New_York)
CET: 2023-03-07 16:00 (Europe/Budapest)
$ tzconv -f ny -t bud "2023-03-14 10:00"
EDT: 2023-03-14 10:00 (America/New_York)
CET: 2023-03-14 15:00 (Europe/Budapest)
$ tzconv -f ny -t bud "2023-03-28 10:00"
EDT: 2023-03-28 10:00 (America/New_York)
CEST: 2023-03-28 16:00 (Europe/Budapest)
$

Custom shell commands for common conversions

If you have a project that spans several time zones, it is convenient to define a shell command for it. The shell command can also eliminate the need for enclosing date-time values in quotes. For example, you can add the following to your shell's startup file (~/.zshrc, ~/.bashrc, or ~/.kshrc):

project_tz() {
    typeset -a opts

    opts=(
        --from-tz America/New_York
        --to-tz America/Los_Angeles
        --to-tz America/Halifax
        --to-tz Asia/Karachi
        --to-tz Asia/Calcutta
    )

    if [ "$*" = "" ]; then
        tzconv ${opts[@]}
    else
        tzconv ${opts[@]} "$*"
    fi
}

Now you can reload the startup file and use project_tz as a shell command:

$ . ~/.zshrc
$ project_tz 2023-04-25 10:00
EDT: 2023-04-25 10:00 (America/New_York)
PDT: 2023-04-25 07:00 (America/Los_Angeles)
ADT: 2023-04-25 11:00 (America/Halifax)
PKT: 2023-04-25 19:00 (Asia/Karachi)
IST: 2023-04-25 19:30 (Asia/Calcutta)
$