I have 2 dates that are both in ISO - 8061 compliant date format.
echo $START
2019-02-14T16:09:13Z
echo $END
2019-02-14T19:43:12Z
Now I want to find the time difference between both. I would prefer the difference to be in hours.
What Ive tried is :
echo "$(($(date -d "$START" '+%s') - $(date -d "$END" '+%s')))"
But it does not work. Any ideas whats the best way to solve this ?
I'd use the dateutils tools.
Then the answer becomes:
> datediff 2019-02-14T16:09:13Z 2019-02-14T19:43:12Z -f "%H hours"
3 hours
echo "$((($(date -d "$END" '+%s') - $(date -d "$START" '+%s'))/60/60))"
Output:
3
On macOS using the built-in BSD date a more verbose solution is required:
echo "$((($(date -jf '%Y-%m-%dT%H:%M:%SZ' "$END" '+%s') - \
$(date -jf '%Y-%m-%dT%H:%M:%SZ' "$START" +%s))/3600 ))"
Output:
3
Similar approach to #Cyrus's answer of converting to epoch first.
Related
I was hoping to get some help with finding the difference in days between two dates.
Date 1: Sysdate
Date2: Mar 20 2022 (future)
What I was trying to do is convert it to EPOCH time, subtract and then divide by 86400 to get the number of days between the two dates. However, I've having issues with the systax. Here's what I've tried:
days_remaining=('date "+%s" -d "Mar 20 2022"'-'date "+%s" -d "$(date '+%b %d %Y')"')/86400
But the above isn't working. Any assistance would be appreciated.
To do calculations in bash you need an arithmetic context (( )). Also, to execute your date commands you have to put them inside $() instead of string quotes ''.
By the way: The last date command in date "+%s" -d "$(date '+%b %d %Y') isn't necessary. date -d 0:00 +%s will print the same unix time.
(( days_remaining = ($(date -d "Mar 20 2022" +%s) - $(date -d 0:00 +%s)) / 86400 ))
you can use this
days_remaining=$(($(($(date "+%s" -d "Mar 20 2022") - $(date "+%s" -d "$(date '+%b %d %Y')"))) / 86400))
I am trying to write a bash script, to merge 24 files in a given day. The requirement changes during Day light saving time changes, where I get 23 or 25 files.
So, with further research I realized that day-light savings begins on the second Sunday of March(23) of every year and ends on first sunday of Novemeber(25).
I need more inputs to get second sunday in a given month to do the check of finding 23 or 25 files for March and November respectively.
Any inputs to help me with this will be really appreciated.
Thank you
Here is the sample code to find 24 files in a day-
if [ -z "$1" ];then
now=$(date -d "-1 days" +%Y-%m-%d);
else now=$1;
fi
load_date='load_date='$now
singlePath="$newPath/$load_date"
fileCount=$(hdfs dfs -ls -R $hdfsPath/$load_date/ | grep -E '^-' | wc -l)
path=$hdfsPath/$load_date
if [ $fileCount -eq 24 ]; then
echo "All files are available for "$load_date;
hadoop fs -cat $path/* | hadoop fs -put - $singlePath/messages.txt
else echo $fileCount" files are available for "$load_date"! Please note, few files are being missed";
fi
I wouldn't hardcode the dates of DST transistions. I would just count "how many hours did today have":
a "normal" day:
$ diff=$(( $(date -d now +%s) - $(date -d yesterday +%s) ))
$ echo $(( diff / 3600 ))
24
"spring forward"
$ diff=$(( $(date -d "2019-03-10 23:59:59" +%s) - $(date -d "2019-03-09 23:59:59" +%s) ))
$ echo $(( diff / 3600 ))
23
"fall back"
$ diff=$(( $(date -d "2019-11-03 23:59:59" +%s) - $(date -d "2019-11-02 23:59:59" +%s) ))
$ echo $(( diff / 3600 ))
25
One thing to note: since bash only does integer arithmetic, if the difference is not 86400 but 86399, you get:
$ echo $((86399 / 3600))
23
So, better to query yesterday's time first in the tiny-but-non-zero chance that the seconds tick over between the 2 date calls:
diff=$(( -$(date -d yesterday +%s) + $(date -d now +%s) ))
Here, $diff will be 86400 or 86401 (for non DST transition days), and dividing by 3600 will give 24 not 23.
I have two dates as follows:
2019-01-06 00:02:10 | END
2019-01-05 23:52:00 | START
How could I calculate and print the difference between START and END dates in seconds?
For above case I would like to get something like:
610
Assuming GNU implementation based OS, you can use date's option %s and -d to calculate the time difference in seconds using command substitution and arithmetic operations.
START="2019-01-05 23:52:00"
END="2019-01-06 00:02:10"
Time_diff_in_secs=$(($(date -d "$END" +%s) - $(date -d "$START" +%s)))
echo $Time_diff_in_secs
Output:
610
Hope this helps!!!
With bash and GNU date:
while read d t x x; do
[[ $x == "END" ]] && end="$d $t"
[[ $x == "START" ]] && start="$d $t"
done < file
end=$(date -u -d "$end" '+%s')
start=$(date -u -d "$start" '+%s')
diff=$(($end-$start))
echo "$diff"
Output:
610
See: man date
What you're asking for is difficult verging on impossible using pure bash. Bash doesn't have any date functions of its own. For date processing, most recommendations you'll get will be to use your operating system's date command, but the usage of this command varies by operating system.
In BSD (including macOS):
start="2019-01-05 23:52:00"; end="2019-01-06 00:02:10"
printf '%d\n' $(( $(date -j -f '%F %T' "$end" '+%s') - $(date -j -f '%F %T' "$start" '+%s') ))
In Linux, or anything using GNU date (possibly also Cygwin):
printf '%d\n' $(( $(date -d "$end" '+%s') - $(date -d "$start" '+%s') ))
And just for the fun of it, if you can't (or would prefer not to) use date for some reason, you might be able to get away with gawk:
gawk 'END{ print mktime(gensub(/[^0-9]/," ","g",end)) - mktime(gensub(/[^0-9]/," ","g",start)) }' start="$start" end="$end" /dev/null
The mktime() option parses a date string in almost exactly the format you're providing, making the math easy.
START="2019-01-05 23:52:00"
END="2019-01-06 00:02:10"
parse () {
local data=(`grep -oP '\d+' <<< "$1"`)
local y=$((${data[0]}*12*30*24*60*60))
local m=$((${data[1]}*30*24*60*60))
local d=$((${data[2]}*24*60*60))
local h=$((${data[3]}*60*60))
local mm=$((${data[4]}*60))
echo $((y+m+d+h+mm+${data[5]}))
}
START=$(parse "$START")
END=$(parse "$END")
echo $((END-START)) // OUTPUT: 610
Was trying to solve the same problem on a non-GNU OS, i.e. macOS. I couldn't apply any of the solutions above, although it inspired me to come up with the following solution. I am using some in-line Ruby from within my shell script, which should work out of the box on macOS.
START="2019-01-05 23:52:00"
END="2019-01-06 00:02:10"
SECONDS=$(ruby << RUBY
require 'date'
puts ((DateTime.parse('${END}') - DateTime.parse('${START}')) * 60 * 60 * 24).to_i
RUBY)
echo ${SECONDS}
# 610
If there are dates as 2010-06-01 and another as 2010-05-15
Using shell script or date command how to get the number of days between the two dates
Thanks..
Using only date and shell arithmetics:
echo $((($(date -d "2010-06-01" "+%s") - $(date -d "2010-05-15" "+%s")) / 86400))
There's a solution that almost works: use the %s date format of GNU date, which prints the number of seconds since 1970-01-01 00:00. These can be subtracted to find the time difference between two dates.
echo $(( ($(date -d 2010-06-01 +%s) - $(date -d 2010-05-15 +%s)) / 86400))
But the following displays 0 in some locations:
echo $((($(date -d 2010-03-29 +%s) - $(date -d 2010-03-28 +%s)) / 86400))
Because of daylight savings time, there are only 23 hours between those times. You need to add at least one hour (and at most 23) to be safe.
echo $((($(date -d 2010-03-29 +%s) - $(date -d 2010-03-28 +%s) + 43200) / 86400))
Or you can tell date to work in a timezone without DST.
echo $((($(date -u -d 2010-03-29 +%s) - $(date -u -d 2010-03-28 +%s)) / 86400))
(POSIX says to call the reference timezone is UTC, but it also says not to count leap seconds, so the number of seconds in a day is always exactly 86400 in a GMT+xx timezone.)
OSX date is different than GNU date. Got it working like this in OSX. This is not portable solution.
start_date=$(date -j -f "%Y-%m-%d" "2010-05-15" "+%s")
end_date=$(date -j -f "%Y-%m-%d" "2010-06-01" "+%s")
echo $(( ($end_date - $start_date) / (60 * 60 * 24) ))
Idea is still same as in the other answers. Convert dates to epoch time, subtract and convert result to days.
Got it
d1=`date +%s -d $1`
d2=`date +%s -d $2`
((diff_sec=d2-d1))
echo - | awk -v SECS=$diff_sec '{printf "Number of days : %d",SECS/(60*60*24)}'
thanks..
Gnu date knows %j to display the day in year:
echo $(($(date -d 2010-06-01 +%j) - $(date -d 2010-05-15 +%j)))
crossing year-boundaries will give wrong results, but since you gave fixed dates ...
How can I print the date which is a day before current time in Bash?
if you have GNU date and i understood you correctly
$ date +%Y:%m:%d -d "yesterday"
2009:11:09
or
$ date +%Y:%m:%d -d "1 day ago"
2009:11:09
If you have BSD (OSX) date you can do it like this:
date -j -v-1d
Wed Dec 14 15:34:14 CET 2011
Or if you want to do date calculations on an arbitrary date:
date -j -v-1d -f "%Y-%m-%d" "2011-09-01" "+%Y-%m-%d"
2011-08-31
date --date='-1 day'
MAC OSX
For yesterday's date:
date -v-1d +%F
where 1d defines current day minus 1 day. Similarly,
date -v-1w +%F - for previous week date
date -v-1m +%F - for previous month date
IF YOU HAVE GNU DATE,
date --date="1 day ago"
More info: https://www.cyberciti.biz/tips/linux-unix-get-yesterdays-tomorrows-date.html
Sorry not mentioning I on Solaris system.
As such, the -date switch is not available on Solaris bash.
I find out I can get the previous date with little trick on timezone.
DATE=`TZ=MYT+16 date +%Y-%m-%d_%r`
echo $DATE
Well this is a late answer,but this seems to work!!
YESTERDAY=`TZ=GMT+24 date +%d-%m-%Y`;
echo $YESTERDAY;
Advanced Bash-scripting Guide
date +%Y:%m:%d -d "yesterday"
For details about the date format see the man page for date
date --date='-1 day'
date -d "yesterday" '+%Y-%m-%d'
or
date=$(date -d "yesterday" '+%Y-%m-%d')
echo $date
Use Perl instead perhaps?
perl -e 'print scalar localtime( time - 86400 ) . "\n";'
Or, use nawk and (ab)use /usr/bin/adb:
nawk 'BEGIN{printf "0t%d=Y\n", srand()-86400}' | adb
Came across this too ... insane!
/usr/bin/truss /usr/bin/date 2>&1 | nawk -F= '/^time\(\)/ {gsub(/ /,"",$2);printf "0t%d=Y\n", $2-86400}' | adb
date --date='-1 day'
Not very sexy but might do the job:
perl -e 'my ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = localtime(time - 86400);$year += 1900; $mon+= 1; printf ("YESTERDAY: %04d%02d%02d \n", $year, $mon, $mday)'
Formated from "martin clayton" answer.
You could do a simple calculation, pimped with an regex, if the chosen date format is 'YYYYMM':
echo $(($(date +"%Y%m") - 1)) | sed -e 's/99$/12/'
In January of 2020 it will return 201912 ;-)
But, it's only a workaround, when date does not have calculation options and other dateinterpreter options (e.g. using perl) not available ;-)
short answer (GNU format):
date +%Y-%m-%d -d "-2 day"
if you are using OSX, but you need create for GNU compatible, install coreutils first
brew install coreutils
then edit your profile with:
#gnu coreutils first
export PATH="/usr/local/opt/coreutils/libexec/gnubin:$PATH"
re-start your terminal, and now you able to use GNU format!
yesterday=`date -d "-1 day" %F`
Puts yesterday's date in YYYY-MM-DD format into variable $yesterday.
#!/bin/bash
OFFSET=1;
eval `date "+day=%d; month=%m; year=%Y"`
# Subtract offset from day, if it goes below one use 'cal'
# to determine the number of days in the previous month.
day=`expr $day - $OFFSET`
if [ $day -le 0 ] ;then
month=`expr $month - 1`
if [ $month -eq 0 ] ;then
year=`expr $year - 1`
month=12
fi
set `cal $month $year`
xday=${$#}
day=`expr $xday + $day`
fi
echo $year-$month-$day
DST aware solution:
Manipulating the Timezone is possible for changing the clock some hours. Due to the daylight saving time, 24 hours ago can be today or the day before yesterday.
You are sure that yesterday is 20 or 30 hours ago. Which one? Well, the most recent one that is not today.
echo -e "$(TZ=GMT+30 date +%Y-%m-%d)\n$(TZ=GMT+20 date +%Y-%m-%d)" | grep -v $(date +%Y-%m-%d) | tail -1
The -e parameter used in the echo command is needed with bash, but will not work with ksh. In ksh you can use the same command without the -e flag.
When your script will be used in different environments, you can start the script with #!/bin/ksh or #!/bin/bash. You could also replace the \n by a newline:
echo "$(TZ=GMT+30 date +%Y-%m-%d)
$(TZ=GMT+20 date +%Y-%m-%d)" | grep -v $(date +%Y-%m-%d) | tail -1
Try the below code , which takes care of the DST part as well.
if [ $(date +%w) -eq $(date -u +%w) ]; then
tz=$(( 10#$gmthour - 10#$localhour ))
else
tz=$(( 24 - 10#$gmthour + 10#$localhour ))
fi
echo $tz
myTime=`TZ=GMT+$tz date +'%Y%m%d'`
Courtsey Ansgar Wiechers
date +%Y:%m:%d|awk -vFS=":" -vOFS=":" '{$3=$3-1;print}'
2009:11:9