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I was going through a tutorial and there I came across a command:

printf "%(%s)T"

The output of this command is:


Could anybody please tell me what is this command and what the output means?

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This seems to be shell dependent. Is your printf a builtin? /usr/bin/printf on Ubuntu 14.04 gives an error: printf: %(: invalid conversion specification. If you're using bash. Try man bash for builtin documentation. – arielf Feb 6 at 20:27
up vote 16 down vote accepted

It's a way to express the formatted time by printf.

The format is:


Where FORMAT is defined by strftime(3).

So to get the epoch time (Time in seconds since 1970-01-01 00:00:00 UTC), we need strftime(3) format %s:

printf "%(%s)T\n"

Note that you also need \n at the end to add a newline as printf (unlike echo) does not add it by default.


$ printf "%(%s)T\n"

$ printf "%(%Y-%m-%d)T\n"

$ printf "%(%Y-%m-%d %H:%M:%S)T\n"
2016-02-01 10:20:27

Just for the sake of completeness, you can also use date command in a similar strftime(3) formatted manner to get the time:

$ date '+%s'

$ date '+%Y-%m-%d'    ## Short form: date -I

$ date '+%Y-%m-%d %H:%M:%S'
2016-02-01 10:22:47
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Thank you so much! – rtecxs Feb 1 at 4:27
@rtecxs I have moved your edit in a different place just to keep things clear..thanks anyway :) – heemayl Feb 1 at 4:33
Ok! Thank you again. – rtecxs Feb 1 at 4:34
Is this feature documented? I didn't see it in the printf(1) man page. – Nate Eldredge Feb 1 at 15:36
@NateEldredge printf is a builtin here (although the external one has the same behavior)..check help printf .. – heemayl Feb 1 at 16:10

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