Convert the current UTC time to different formats.

time format examples.md

Time format examples

Gets the current UTC time to seconds accuracy (max available with date). Using date and sed so these can run in Alpine Linux.

As file path

For example: 1999/12/31/23/59/59

Ash

date -Iseconds -u | sed -En '1{s/[-+:T]/\//g; s/^(.{0,19}).*$/\1/g; p}'

JS

(new Date()).toISOString().replace(/[-:T]/g, '/').slice(0, 19)

Ramda

const ensure_int = R.unless(R.is(Number), parseInt)
const timestamp_to_iso8601_text = R.pipe(ensure_int, R.constructN(1, Date), R.invoker(0, 'toISOString'))
const as_path = R.pipe(timestamp_to_iso8601_text, R.replace(/[-:T]/g, '/'), R.slice(0, 19))
as_path(Date.now())

To include milliseconds:

const as_path = R.pipe(timestamp_to_iso8601_text, R.replace(/[-.:T]/g, '/'), R.init)

Note the Ramda example is longer because it creates other functions that may be useful.

To convert path back to timestamp:

const collapse_path = R.pipe(R.split('/'), R.map(parseInt), R.apply(R.constructN(7, Date)), R.invoker(0, 'valueOf'))

In Docker tag friendly format

For example: 19991231t235959

Ash

With cut and tr:

date -Is -u | cut -c -19 | tr -d '-' | tr -d ':' | tr 'T' 't'

With sed:

date -Iseconds -u | sed -En '1{s/[-+:]//g; s/^(.{0,15}).*$/\L\1/g; p}'

Links

https://www.gnu.org/software/sed/manual/sed.html