Date math in ksh

[chipjustis]

Anybody know of a quick way to do date math in ksh? I know I could write my own considering leap years and 28 day months, but is there anything simple in ksh similar to Excel for instance?

I'd like to do:

date1 - date2 = days
date1 + days = date2
date1 - days = date2

I also realize Pearl, C, etc. have date routines, but I'm looking for something the within ksh, maybe awk, sed etc?

Thanks

 

[olded]

Hi:

Date arithmetic has been discussed before at Tek-tips. Take a look at these threads:

thread58-543806

thread219-519109

thread822-514837

Regards,

Ed

 

[pmurray99]

This might help.

expects the 1st part of your $TZ to look like :

EDT-11EST-10

If you don't want to change the TZ in your current shell, set it in the script that calls the get_date function.

#!/usr/bin/ksh

#
# get_date
#
# function to return day month year relative to today.
# $1 = +n|-n
# $2 = y, display on tty

get_date()
{

[[ $# -lt 1 ]] &&
{
message " Usage: get_day -n|+n"
return 1
}

offset=$(print $TZ | sed -e "s/.*$(date +%Z)\([+-]*[0-9][0-9]*\).*/\1/&quot

[[ $(expr $1 : ^[+-]) -eq 0 ]] &&
{
message "Invalid argument "
return 1
}

if [ $(expr $1 : ^[-]) -ne 0 ]; then
n="+"$((${1#-}*24))
else
n="-"$((${1#+}*24))
fi

offset=$(($offset${n}))
day=$(TZ=XXX$offset date +%d)
mon=$(TZ=XXX$offset date +%m)
year=$(TZ=XXX$offset date +%Y)

[[ $# -eq 2 ]] && print "$day.$mon.$year"
return 0
}