How to convert timestamps to dates in Bash?

Question

I need a shell command or script that converts a Unix timestamp to a date. The input can come either from the first parameter or from stdin, allowing for the following usage patterns:

ts2date 1267619929

and

echo 1267619929 | ts2date

Both commands should output "Wed Mar 3 13:38:49 2010".

score 662 · Accepted Answer · edited Feb 19 '22 at 23:36

662

On systems with GNU Coreutils >= 5.3.0, e.g. Linux you can use:

date -d @1267619929

edited Feb 19 '22 at 23:36

Cristian Ciupitu

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answered Mar 03 '10 at 12:47

a'r

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One-liner: `date -d @$(date -u +%s)` – Mike Atlas Jan 05 '16 at 17:30
34

What is the `@` for? I don't see that in the GNU man page at all. – Mark E. Haase Feb 01 '16 at 03:06
19

@mehaase - the man page notes that the date string is too complex to be documented in the manpage, so it is described in info: **info '(coreutils) date invocation'** – MByD Mar 23 '16 at 08:48
18

`brew install coreutils; gdate -d @1267619929` – Mark Fox May 23 '17 at 22:21
7

`info 'Date input formats'` gets you straight to `date`'s formatting info node, with the pertinent Robert Grudin quote, and then a menu of format specifiers. – mike Aug 19 '19 at 01:02
1

In a pipe: `echo 1267619929 | date -d @$( – rkok Apr 18 '20 at 17:50

score 208 · Answer 2 · edited Dec 22 '16 at 12:52

208

date -r <number>

works for me on Mac OS X.

edited Dec 22 '16 at 12:52

Mundi

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answered Oct 26 '12 at 13:49

rafaelzlisboa

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Yes, but it doesn't handle fractions of a second. – mgold Oct 31 '13 at 22:21
1

And it's confusing because it's not working in that way on most linux systems, because: freddy@hades ~ % date --help | grep -- -r -r, --reference=FILE display the last modification time of FILE – frank42 Sep 19 '17 at 16:02
8

while the comments on this answer are true, these are not rafa's fault, and they don't diminish his answer. – mike Aug 19 '19 at 01:07

score 30 · Answer 3 · edited Feb 19 '22 at 23:47

30

This version is similar to chiborg's answer, but it eliminates the need for the external tty and cat. It uses date, but could just as easily use gawk. You can change the shebang and replace the double square brackets with single ones and this will also run in sh.

#!/bin/bash
LANG=C
if [[ -z "$1" ]]
then
    if [[ -p /dev/stdin ]]    # input from a pipe
    then
        read -r p
    else
        echo "No timestamp given." >&2
        exit
    fi
else
    p=$1
fi
date -d "@$p" +%c

edited Feb 19 '22 at 23:47

Cristian Ciupitu

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answered Mar 03 '10 at 14:11

Dennis Williamson

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+1: very complete answer and I think date is faster than gawk. – Bruno Brant Mar 03 '10 at 14:19
@Bruno, how do you know date is faster than gawk.? – ghostdog74 Mar 03 '10 at 14:23
3

@Bruno, @ghostdog74: On my system, `gawk` is (very roughly) 15% faster than `date` in a timed `for` loop consisting only of `gawk 'BEGIN { print strftime("%c", 1256571985); }'` or `date -d '@1256571985' +%c` with output redirected to `/dev/null`. – Dennis Williamson Mar 03 '10 at 14:57
I chose this as the "best" answer because the script satisfies the "date input via parameter or stdin" better. Thanks for enhancing my shellscripting skills! – chiborg Mar 08 '10 at 21:31
1

date is marginally (5%) faster than gawk for me (mac osx 10.9.2, date 8.23, gawk 4.1.1), but the real advantage of (g)awk is to accept a pipe of a column of many timestamps (see my answer below), which makes the script e.g. 250x as fast for 1000 timestamps. – webb Sep 25 '14 at 23:10
3

Note that my answer meets the OP's requirements as stated in the question, but the now accepted answer doesn't. – Dennis Williamson Sep 26 '14 at 15:19

score 18 · Answer 4 · edited Sep 11 '15 at 09:40

18

You can use GNU date, for example,

$ sec=1267619929
$ date -d "UTC 1970-01-01 $sec secs"

or

$ date -ud @1267619929

edited Sep 11 '15 at 09:40

Peter Mortensen

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answered Mar 03 '10 at 12:51

ghostdog74

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score 13 · Answer 5 · answered Apr 19 '19 at 08:28

13

You can get formatted date from timestamp like this

date +'%Y-%m-%d %H:%M:%S' -d "@timestamp"

answered Apr 19 '19 at 08:28

andranikasl

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Other way around: date -ud "@1585667718" +'%Y-%m-%d %H:%M:%S' – AndiAna Mar 31 '20 at 18:15

Blago · Answer 6 · 2021-09-16T16:45:00.393

11

I use this cross-platform one-liner:

date -d @1267619929 2>/dev/null || date -r 1267619929

It should work both in macOS and modern versions of popular Linux distributions.

edited Sep 16 '21 at 16:45

answered Dec 16 '19 at 07:31

Blago

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score 10 · Answer 7 · answered Mar 03 '10 at 12:45

10

You can use this simple awk script:

#!/bin/gawk -f   
{ print strftime("%c", $0); }

Sample usage:

$ echo '1098181096' | ./a.awk 
Tue 19 Oct 2004 03:18:16 AM PDT
$

answered Mar 03 '10 at 12:45

codaddict

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This doesn't fit the first usage - sometimes I don't want to echo the TS and use a parameter instead. – chiborg Mar 03 '10 at 12:52
On some old busybox version, `date -s @` doesn't work, and `awk` still does! An example without a stdin would be helpful too. – Victor Sergienko Jan 31 '17 at 18:07

score 9 · Answer 8 · answered Sep 13 '17 at 17:27

Since Bash 4.2 you can use printf's %(datefmt)T format:

$ printf '%(%c)T\n' 1267619929
Wed 03 Mar 2010 01:38:49 PM CET

That's nice, because it's a shell builtin. The format for datefmt is a string accepted by strftime(3) (see man 3 strftime). Here %c is:

%c The preferred date and time representation for the current locale.

Now if you want a script that accepts an argument and, if none is provided, reads stdin, you can proceed as:

#!/bin/bash

if (($#)); then
    printf '%(%c)T\n' "$@"
else
    while read -r line; do
        printf '%(%c)T\n' "$line"
    done
fi

score 6 · Answer 9 · edited Apr 17 '14 at 07:58

6

I use this when converting log files or monitoring them:

tail -f <log file> | gawk \
'{ printf strftime("%c", $1); for (i=2; i<NF; i++) printf $i " "; print $NF }'

edited Apr 17 '14 at 07:58

Emissary

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answered Apr 17 '14 at 07:24

user3544224

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exactly what I was looking for, can be shortened to `awk '{ printf strftime("%c: ", $1); $1 = ""; print $0; }'` – ChrisWue May 27 '19 at 07:36

score 6 · Answer 10 · answered Oct 24 '17 at 21:46

6

In OSX, or BSD, there's an equivalent -r flag which apparently takes a unix timestamp. Here's an example that runs date four times: once for the first date, to show what it is; one for the conversion to unix timestamp with %s, and finally, one which, with -r, converts what %s provides back to a string.

$  date; date +%s; date -r `date +%s`
Tue Oct 24 16:27:42 CDT 2017
1508880462
Tue Oct 24 16:27:42 CDT 2017

At least, seems to work on my machine.

$ uname -a
Darwin XXX-XXXXXXXX 16.7.0 Darwin Kernel Version 16.7.0: Thu Jun 15 17:36:27 PDT 2017; root:xnu-3789.70.16~2/RELEASE_X86_64 x86_64

answered Oct 24 '17 at 21:46

Daniel Farrell

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If you already have a timestamp value and you just need to find the equivalent date, in OS X you can just type this at the command line: date -r 1509453417 – Noel Whitemore Oct 31 '17 at 12:21
1

That's true. If you look at my answer, I'm actually demonstrating that. – Daniel Farrell Nov 14 '17 at 21:41

chiborg · Answer 11 · 2010-03-03T13:41:54.293

3

I have written a script that does this myself:

#!/bin/bash
LANG=C
if [ -z "$1" ]; then
    if [  "$(tty)" = "not a tty" ]; then
            p=`cat`;
    else
            echo "No timestamp given."
            exit
    fi
else
    p=$1
fi
echo $p | gawk '{ print strftime("%c", $0); }'

edited Mar 03 '10 at 13:41

answered Mar 03 '10 at 12:42

chiborg

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score 3 · Answer 12 · answered Sep 25 '14 at 23:08

In this answer I copy Dennis Williamson's answer and modify it slightly to allow a vast speed increase when piping a column of many timestamps to the script. For example, piping 1000 timestamps to the original script with xargs -n1 on my machine took 6.929s as opposed to 0.027s with this modified version:

#!/bin/bash
LANG=C
if [[ -z "$1" ]]
then
    if [[ -p /dev/stdin ]]    # input from a pipe
    then
        cat - | gawk '{ print strftime("%c", $1); }'
    else
        echo "No timestamp given." >&2
        exit
    fi
else
    date -d @$1 +%c
fi

score 2 · Answer 13 · answered Mar 22 '16 at 08:58

2

some example:

$ date
Tue Mar 22 16:47:06 CST 2016

$ date -d "Tue Mar 22 16:47:06 CST 2016" "+%s"
1458636426

$ date +%s
1458636453

$ date -d @1458636426
Tue Mar 22 16:47:06 CST 2016

$ date --date='@1458636426'
Tue Mar 22 16:47:06 CST 2016

answered Mar 22 '16 at 08:58

kai

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Brad Parks · Answer 14 · 2019-11-15T12:20:51.167

While not pure bash, the following script will convert timestamps of length 13 in a string to their equivalent date in your local timezone using perl

timestamp_to_date.sh

#!/usr/bin/env bash
IT=$(cat /dev/stdin)
re='(.*)([0-9]{13})(.*)'
while [[ $IT =~ $re ]]; do
  TIMESTAMP=${BASH_REMATCH[2]}
  AS_DATE=$(echo "$TIMESTAMP" | perl -pe 's/([\d]{10})([\d]{3})/localtime $1/eg;')
  IT="${IT/$TIMESTAMP/$AS_DATE}"    
done
echo "$IT"

input

{"timestamp":"1573121629939","level":"DEBUG","thread":"http-nio-15372-exec-3","logger":"org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor"}

output

$ cat input | timestamp_to_date.sh

{"timestamp":"Thu Nov  7 06:13:49 2019","level":"DEBUG","thread":"http-nio-15372-exec-3","logger":"org.springframework.web.servlet.mvc.method.annotation.RequestResponseBodyMethodProcessor"}

score 0 · Answer 15 · answered Dec 14 '20 at 13:45

0

I had to convert timestamps inline in my bash history to make sense to me.

Maybe the following coming from an answer to How do I replace a substring by the output of a shell command with sed, awk or such? could be interesting to other readers too. Kudos for the original sed inline code go to @Gabriel.

cat ~/.bash_history | sed "s/^#\([0-9]\+\)$/echo -n '#'; date -u --d @\1 '\+\%Y-\%m-\%d \%T'/e" | less

answered Dec 14 '20 at 13:45

stefan123t

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2
5

you should check out https://jb55.com/datefmt, I've written a C util that does just that, and it should be much faster. – William Casarin Dec 10 '21 at 16:35

score 0 · Answer 16 · answered Dec 10 '21 at 16:33

If you're looking to format many timestamps all at once, I've written a C util called datefmt that formats timestamps in a text stream:

Let’s say we have some logs that contain unix timestamps:

$ cat logs.txt

EVENTS  1638499687   blahblah log1
EVENTS  1638499717   blahblah log2

We can pipe this log into datefmt to convert these timestamps into human-readable dates:

$ <logs.txt datefmt

EVENTS  2021-12-02 18:48   blahblah log1
EVENTS  2021-12-02 18:48   blahblah log2

Of course you can customize the format as well:

$ <logs.txt datefmt "DATE:'%m-%d %R'"

EVENTS  DATE:'12-02 18:48'   blahblah log1
EVENTS  DATE:'12-02 18:48'   blahblah log2

I've packaged this in NixOS, hopefully it will trickle out to other distros soon, but for now you will need to download the tarball and build it with make

score -11 · Answer 17 · answered Mar 03 '10 at 12:43

-11

In PHP

$unix_time = 1256571985;

echo date("Y-m-d H:i:s",$unix_time)

answered Mar 03 '10 at 12:43

Lucas

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Nice, but I just wanted to use bash. – chiborg Mar 03 '10 at 12:53

How to convert timestamps to dates in Bash?

17 Answers17

timestamp_to_date.sh

input

output

Linked