Return to Answer

...because you mix up calender days and 24h-periods in your OP. Sometimes we want this, sometimes that.

touch -d '2019-11-19 0800' thismorning lets you easily create testfiles:

]# find -name '*n*g*' -daystart -mtime 0 -ls 
      Nov 19 08:00 ./thismorning
]# find -name '*n*g*' -daystart -mtime 1 -ls 
      Nov 18 22:30 ./lastnight
      Nov 18 08:30 ./lastmorning
]# find -name '*n*g*'  -mtime 0 -ls 
      Nov 18 22:30 ./lastnight
      Nov 19 08:00 ./thismorning
]# find -name '*n*g*'  -mtime 1 -ls 
      Nov 17 22:00 ./lastlastnight
      Nov 18 08:30 ./lastmorning
 

(I snipped away -ls output fields -- only left the dates and filenames)

]# find -name '*n*g*'; date         
./lastnight
./thismorning
./lastlastnight
./lastmorning
Tue Nov 19 10:34:33 UTC 2019
]# find -name '*n*g*' -daystart -mtime 2 -ls 
   Nov 17 22:00 ./lastlastnight
]# 

...because you mix up calender days and 24h-periods in your OP. Sometimes we want this, sometimes that.

man find, -atime:

...so to match -atime +1, a file has to have been accessed at least two days ago.

Option -daystart changes the interpretation.

...because you mix up calender days and 24h-periods in your OP. Sometimes we want this, sometimes that.

Why seconds since epoch?

If you want to know how long something lasted, i.e. the difference of two dates, our calender has these irregularities (the months). So either use your knuckles, know about emperors Julius and Augustus, or use brute force via seconds.

From 30.7. to 1.9. is three days longer than 30.1. to 1.3., and it even depends on leap years.

today, 5:30 pm and tomorrow 6:00 am are

• different days (calendar wise)
• only half a day apart (day=duration of 24x60x60 seconds)

From your expiration_date I deduct you want to count the 24h periods passed. That means at 1:00am most of "yesterday" is unaffected.

I tested and correted the date command

]# date -d "-1 day" +%s
1574003538
]# date -d "-0 day" +%s
1574089945

The difference is 86407 i.e 24x60x60.

(And if somebodey asks me: "What were you doing at date -d @1574089945?" I can say: "I was editing a command for seven seconds")

]# find . -atime 1
./here.sh
]# find . -atime +0 -atime -2
./here.sh
]# ls -l here.sh 
-rw-r--r-- 1 root root 154 Nov 16 21:37 here.sh

Now is Nov 18 16:43. So there is one full 24h period between.

man find, -atime:

...so to match -atime +1, a file has to have been accessed at least two days ago.

Option -daystart changes the interpretation:

-daystart
 Measure times (for -amin, -atime, -cmin, -ctime, -mmin, and  -mtime)
 from the beginning of today rather than from 24 hours ago.  

...because you mix up calender days and 24h-periods in your OP. Sometimes we want this, sometimes that.

Why seconds since epoch?

If you want to know how long something lasted, i.e. the difference of two dates, our calender has these irregularities (the months). So either use your knuckles, know about emperors Julius and Augustus, or use brute force via seconds.

From 30.7. to 1.9. is three days longer than 30.1. to 1.3., and it even depends on leap years.

today, 5:30 pm and tomorrow 6:00 am are

• different days (calendar wise)
• only half a day apart (day=duration of 24x60x60 seconds)

From your expiration_date I deduct you want to count the 24h periods passed. That means at 1:00am most of "yesterday" is unaffected.

I tested and correted the date command

]# date -d "-1 day" +%s
1574003538
]# date -d "-0 day" +%s
1574089945

The difference is 86407 i.e 24x60x60.

(And if somebodey asks me: "What were you doing at date -d @1574089945?" I can say: "I was editing a command for seven seconds")

]# find . -atime 1
./here.sh
]# find . -atime +0 -atime -2
./here.sh
]# ls -l here.sh 
-rw-r--r-- 1 root root 154 Nov 16 21:37 here.sh

Now is Nov 18 16:43. So there is one full 24h period between.

man find, -atime:

...so to match -atime +1, a file has to have been accessed at least two days ago.

Option -daystart changes the interpretation.

...because you mix up calender days and 24h-periods in your OP. Sometimes we want this, sometimes that.

Why seconds since epoch?

If you want to know how long something lasted, i.e. the difference of two dates, our calender has these irregularities (the months). So either use your knuckles, know about emperors Julius and Augustus, or use brute force via seconds.

From 30.7. to 1.9. is three days longer than 30.1. to 1.3., and it even depends on leap years.

today, 5:30 pm and tomorrow 6:00 am are

• different days (calendar wise)
• only half a day apart (day=duration of 24x60x60 seconds)

From your expiration_date I deduct you want to count the 24h periods passed. That means at 1:00am most of "yesterday" is unaffected.

I tested and correted the date command

]# date -d "-1 day" +%s
1574003538
]# date -d "-0 day" +%s
1574089945

The difference is 86407 i.e 24x60x60.

]# find . -atime 1
./here.sh
]# find . -atime +0 -atime -2
./here.sh
]# ls -l here.sh 
-rw-r--r-- 1 root root 154 Nov 16 21:37 here.sh

Now is Nov 18 16:43. So there is one full 24h period between.

man find, -atime:

...so to match -atime +1, a file has to have been accessed at least two days ago.

Option -daystart changes the interpretation.

...because you mix up calender days and 24h-periods in your OP. Sometimes we want this, sometimes that.

Why seconds since epoch?

If you want to know how long something lasted, i.e. the difference of two dates, our calender has these irregularities (the months). So either use your knuckles, know about emperors Julius and Augustus, or use brute force via seconds.

From 30.7. to 1.9. is three days longer than 30.1. to 1.3., and it even depends on leap years.

today, 5:30 pm and tomorrow 6:00 am are

• different days (calendar wise)
• only half a day apart (day=duration of 24x60x60 seconds)

From your expiration_date I deduct you want to count the 24h periods passed. That means at 1:00am most of "yesterday" is unaffected.

I tested and correted the date command

]# date -d "-1 day" +%s
1574003538
]# date -d "-0 day" +%s
1574089945

The difference is 86407 i.e 24x60x60.

(And if somebodey asks me: "What were you doing at date -d @1574089945?" I can say: "I was editing a command for seven seconds")

]# find . -atime 1
./here.sh
]# find . -atime +0 -atime -2
./here.sh
]# ls -l here.sh 
-rw-r--r-- 1 root root 154 Nov 16 21:37 here.sh

Now is Nov 18 16:43. So there is one full 24h period between.