Date Substraction

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# 1  
Old 03-28-2001

In Unix script, how to get a "date - 1" ie, yesterday?
# 2  
Old 03-28-2001

# figure out what yesterday was.
date '+%Y %m %d' |
 read year month day

 day=`expr "$day" - 1`
 case "$day" in
 month=`expr "$month" - 1`
 case "$month" in
 year=`expr "$year" - 1`

 day=`cal $month $year | grep . | fmt -1 | tail -1`

 echo "Yeseterday was: $day $month $year"

Last edited by Yogesh Sawant; 05-20-2010 at 10:53 AM.. Reason: added code tags
# 3  
Old 03-28-2001
or if you are using GNU date, simply do:

date --date=yesterday

Last edited by Yogesh Sawant; 05-20-2010 at 10:52 AM.. Reason: added code tags
# 4  
Old 03-28-2001
MySQL Date Substraction

It works. Thank you.
# 5  
Old 03-29-2001
in Perl there is really handy way to manipulate Date
print scalar localtime (time() - 86400 * n);

it will substract n from current date and print the date

print scalar localtime (time() - 86400 * 1); #yesterday
print scalar localtime (time() - 86400 * 30); #Date of 30 days back

To get date four days from now
print scalar localtime (time() + 86400 * 4);

and so on....

Last edited by Yogesh Sawant; 05-20-2010 at 10:53 AM.. Reason: added code tags
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