Convert Current Date to Unix timestamp but using Days

Question

In Solaris, I am trying to write a shell script that converts current date to the number of days after 1/1/1970 for Unix. This is because etc/shadow isn't using Epoch time but instead a 'days format'

i.e "root:G9yPfhFAqvlsI:15841::::::" where the 15841 is a date.

So in essence what command do I use to find out the epoch time for now and then convert that to days.

What is 15841? The number of seconds after the Epoch began? If so, you should be able to divide it by 60*60*24 to get the number of days. — ahoffer
– ahoffer, Commented Jul 15, 2014 at 18:53
15841 is the number of days after 1/1/1970 so I'm trying to find out what the command is to print today's date into the format for days @ahoffer — user3508234
– user3508234, Commented Jul 15, 2014 at 19:00
You can use echo $(($(nawk 'BEGIN {print srand()}') / 86400 )). — alvits
– alvits, Commented Jul 15, 2014 at 19:27

glenn jackman · Accepted Answer · 2014-07-15 19:07:23Z

1

You probably don't have GNU tools, which might make things easier. This is simple enough though:

perl -le 'print int(time/86400)'

answered Jul 15, 2014 at 19:07

glenn jackman

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2 Comments

glenn jackman Over a year ago

If you're using this to obtain a uid, better not create 2 users on the same day.

user3508234 Over a year ago

Thank you @glennjackman is there anyway to do this without perl?

ahoffer · Accepted Answer · 2014-07-15 19:21:28Z

0

I found some pseudo code to calculate it from the basics:

if month > 2 then month=month+1 else month=month+13 year=year-1 fi day=(year*365)+(year/4)-(year/100)+(year/400)+(month*306001/10000)+day days_since_epoch=day-719591

Credit: http://www.unix.com/shell-programming-and-scripting/115449-how-convert-date-time-epoch-time-solaris.html). On the same forum thread, another poster said this would work in Solaris:

truss /usr/bin/date 2>&1 | grep ^time | awk -F"= " '{print $2}'

answered Jul 15, 2014 at 19:21

ahoffer

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4 Comments

user3508234 Over a year ago

i put 'truss /usr/bin/date 2>&1 | grep ^time | awk -F"= " '{print $2}'' into a variable now do you know how I would divide that variable using the "variable" /8600 ?

alvits Over a year ago

@user3508234 - it will be easier to use nawk's srand(). If you are running bash you can assign to var like (( var = $(nawk 'BEGIN {print srand()}') / 86400 )). If you still prefer the above method, you can use (( var /= 86400 )) on bash or var=`echo $var / 86400 | bc` on non-bash.

glenn jackman Over a year ago

@user3508234: truss /usr/bin/date 2>&1 | nawk '$1 == "time()" {print int($NF/86400)}'

glenn jackman Over a year ago

@alvits, might as well do the division in awk: nawk 'BEGIN {print int(srand()/86400)}'

alvits · Accepted Answer · 2014-07-16 17:03:04Z

Solaris date utility doesn't support %s format. However, nawk utility has srand() function that returns date in seconds when there's no parameter passed to it.

nawk 'BEGIN {print srand()}'

Results in

1405529923

To get the days instead of seconds, you can divide the result by 86400.

nawk 'BEGIN {printf("%d", srand() / 86400)}'

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