todo

The Linux command.

See also:

• Linux date and time setting

• strftime

Usage ∞

yyyy-mm-dd ∞

date +%Y-%m-%d

yyyy-mm-dd_hh-mm ∞

date  --utc  +'%Y-%m-%d_%H-%M'

This uses 24-hour time and UTC to maintain sortability and avoid timezone confusion.

Maybe you prefer something which isn’t a colon (:) but looks like a colon

date  --utc  +'%Y-%m-%d_%H꞉%M'

Timezone Conversion ∞

props to http://www.wiki.balug.org/wiki/doku.php?id=balug:covid-19

On any system with GNU date(1), included in GNU coreutils, you can convert a remote event’s time/date to your local timezone’s time/date using syntax as per the following example:

date -d 'TZ="Europe/London" 2021-02-13 14:00'

Sat Feb 13 06:00:00 PST 2021

GNU date(1) will use your system’s TZ database to convert time/date correctly, including compensating for DST / Standard Time issues at either your and/or the remote location.

It is also possible to generalize that syntax, to convert to a timezone differing from your local timezone, by prefacing the foregoing command with an output-timezone qualifier, e.g., as follows requesting conversion to Arizona time/date:

TZ='America/Phoenix' date -d 'TZ="Europe/London" 2021-02-13 14:00'

Sat Feb 13 07:00:00 MST 2021

Quoting must be as shown, and timezone names must be correct, or you will get errors or (worse) silent ignoring of the provided timezone qualifier.

Use canonical TZ database names.

On MacOS ∞

(macOS)

MacOS uses BSD‘s date(1) which lacks the -d option.

Homebrew will supply gdate

brew install coreutils

On Windows ∞

(Windows)

Windows Subsystem for Linux 2 has the appropriate date. It is likely that Windows Subsystem for Linux does too.

Otherwise, install GnuWin32 for date.

Web ∞

• https://www.timeanddate.com/worldclock/converter.html

Resources ∞

• https://www.wiki.balug.org/wiki/doku.php?id=balug:covid-19#timezone_conversion

• https://www.mpaoli.net/~michael/bin/Times

#!/bin/sh
for tz in \
        'PST8PDT US/Pacific' \
        'CST6CDT US/Central' \
        GMT0 \
do 
        TZ="$(set -- $tz; printf '%s\n' "$1")"
        printf '%s\n' "$(TZ="$TZ" date -Iseconds "$@") $(TZ="$TZ" date "$@") $tz"
done |
sort -u

#       'EST5EDT US/Eastern' \
#       Europe/London \
#       Asia/Kolkata
# (for TZ in $(cd /usr/share/zoneinfo && find * -follow -type f -exec file -L \{\} \; | sed -ne 's;^\([^:]*\): timezone data,.*$;\1;p'); do export TZ; date -d @1707350400 | tr '\012' ' '; echo "$TZ"; done) | sort -k 3,3bn -k 4,4