How to get last month?

[volcano]

Hi, would you tell me how I can get the last month of the year? For example, now is 200401, my wanted value is 200312. I know that the code of getting last day can be :

TZ="$TZ+24"
export TZ
YESTERDAY=`date +%Y%m%d`

can getting last month be similar to this?

Thank you

 

[aigles]

A solution :
[tt]
year=`date +%Y`
year=`expr $year - 1`
last_month=${year}12
echo $last_month
[/tt]
The same with ksh
[tt]
last_month=$(( $(date +%Y) -1 ))12
echo $last_month
[/tt]

Jean Pierre.

 

[volcano]

Hi thanks for your reply. I am afraid I expressed a wrong meaning. I mean I want a value of the previous month compared to the current month. That's not the last month of my specific year. For example, today is 6 Feb 2004, then my wanted value is 200401. If today was 20 Jan 2005, then my wanted value was 200412.

Please help, thanks!

 

[aigles]

[tt]
year=`date +%Y`
month=`date +%m`
month=`expr $month - 1`
if [ $month -eq 0 ]
then
year=`expr $year -1`
month=12
fi
last_month=`printf "%04d%02d\n" $year $month`
echo $last_month
[tt]
Ksh
[tt]
typeset -Z4 year=$(date +%Y)
typeset -Z2 month=$(( $(date +%m) -1 ))
if [ $month -eq 0 ]
then
(( year -= 1 ))
month=12
fi
last_month=${year}${month}
echo $last_month
[tt]


Jean Pierre.