'(The 14-Digit Timestamp, et al)
Audience: anyone
The so-called “14-digit timestamp” is turning up in more and more places. For those unfamiliar, it takes the form of:
YYYYMMDDhhmmss
I’ve seen it recently in Migratus and
Rails/Cap deploys (current symlink), and it’s been used widely by MySQL.
They’re pretty handy for setting to-the-second precision for ordering of things,
like database migrations. And, they’re fairly human-parsable.
At the time of this writing, the 14-digit time is 20160114180301. If you find
that hard to eye-parse, here’s a (really ugly) shell function to help:
dt14p() { sed -r 's/([0-9]{4})([0-9]{2})([0-9]{2})([0-9]{2})([0-9]{2})([0-9]{2})/\1-\2-\3 \4:\5:\6/' <<< $1 }
% dt14p 20160114184117 2016-01-14 18:41:17
This enables date (and your eyes) to parse it.
Something I see missed on occasion is the use of UTC on such stamps. That seems pretty important if you’re using these for ordering, and have a time zone-distributed team.
14s are not to be confused with the 10-digit epoch-second-stamp, or MongoDB’s similar 64-bit 13-digit stamp (1452758412345).
You might also find weekstamps useful for writing weekly reports and other organization.
Generating a 14-digit stamp
date --utc +%Y%m%d%H%M%S
Why not make it an alias?
alias dt14='date --utc +%Y%m%d%H%M%S'
And use it often:
mkdir `dt14`-something
(I usually find the 8-digit datestamp dt8 to be sufficient for directory
names.)
While we’re at it, here are some other useful stamping aliases. I use the dt
prefix to make them easy to both remember and tab-complete. Some of these I use
every day. Put them in your .zshrc
and enjoy!
alias dt='date +%Y%m%d' # frequent 8-digit stamp: 20160114
alias dt8=dt
alias day=dt
alias dts='date +%s' # seconds since epoch: 1452795263
alias dte=dts
alias dt10=dts
alias dtep='print "use this to parse: date -d @123..."' # parse the epoch
alias dtp='date -d ' # parse
alias dttm='date --utc +%Y%m%d%H%M%S' # datetime: 20160114192940
alias dt14=dttm
alias dt13=dtb
alias dto='date +%Y%j' # ordinal date: 2016016 (16th day of year)
alias dt7=dto
# https://en.wikipedia.org/wiki/ISO_week_date
alias dtwk='date +W%V' # week date: W02
alias dtyrwk='date +%GW%V' # year week date: 2016W02
# ISO 8601
alias dtw='date +%G-W%V-%' # year week: 2016-W02-4
alias dti='date -I' # ISO-8601: 2016-01-14
alias dt-=dti
alias dti='date -u +%Y%m%dT%H%M%S' # 20160111T173110Z
alias dti-='date -u +%Y-%m-%dT%H:%M:%SZ' # 2016-01-11T17:31:10Z
alias dti0='date -u -Iseconds' # 2016-01-11T17:31:10+0000
alias dto-='date +%Y-%j' # ordinal date: 2016-016
alias dtb="date-iso2bson.rb <<<\"'`dt-`'\"" # for mongo bson(Note: this is using date from GNU Coreutils. Yours may be different if you’re
not on Linux.)