[CentOS] OT ? Shell script

[Robert]

Maciej Żenczykowski wrote:

> On Sun, 4 Dec 2005, Robert wrote:
>
>> Does anyone have an elegant solution for finding the date of the 3rd 
>> Monday each month and the date of the Sunday preceding? (Sunday 
>> shouldn't be beyond my capabilities, once the Monday part is worked 
>> out.)
>> For the past several years, I've been handling the chore using a file 
>> with a manually input list of dates -- which is about as elegant as 
>> driving a tack with a sledge hammer.
>> _______________________________________________
>
> How about something like:
>
> YEAR=2005
> MONTH=12
> for ((DAY=1;DAY<=31;++DAY)); do
> LC_ALL=C TZ=UTC date -d "$YEAR-$MONTH-$DAY"
> done | grep "^Mon " | head -n 3 | tail -n 1
>
> Possibly without the TZ=UTC depending on your needs...
>
> Cheers
> MaZe? 

Considering my nebulous request and your apparent lack of expertise in 
applied clairvoyance, fine.
The "3rd Monday" part is used in generating reminders to a each of a 
group of OldFarts that gets together monthly to inventory aches, pains 
and, yes, empty chairs. The "Sunday before" requirement will be used to 
run a script (already working) to create a series of image files 
containing critical stuff, to be burned (manually) to DVDs to go with me 
to the meeting, to be given to a trusted person for safekeeping.

The following is what I have now, stripped down to the bare essentials 
for clarity(?):

[rj at mavis ~]$ crontab -l
MAILTO=""
* * * * * /home/rj/meetdate

[rj at mavis ~]$ cat meetdate
#!/bin/bash
# meetdate
/home/rj/NSS.sh 10/17/2005 11/21/2005 12/19/2005 1/16/2006 2/20/2006 
3/20/2006 (etc., etc., etc....)
[rj at mavis ~]$

[rj at mavis ~]$ cat NSS.sh
#!/bin/bash
while [ $((`date -d $1 +%s` + 55800)) -le $((`date +%s`)) ] ; do
shift
MM=$((`date -d $1 +%s` + 55800)) # 3:30 PM on the date passed
MB=$((`date -d $1 +%s` - 88200)) # 4:30 AM on the previous day
# I want to match only date, hour and minute.
MBS=`date -d "1/1/1970 + $MB seconds" +%D" "%H":"%M`
done
if [ "`date +%D" "%H":"%M`" = "$MBS" ] ; then
#
# Go execute backup script
#
#
echo Finished Backup Crap
else
echo "Nope! Next backup will be at " $MBS
echo "Meeting will be on " $1" at 3:30 PM"
fi
[rj at mavis ~]$

As it stands now, I have to manually edit the file "meetdate" from time 
to time, adding another year or two of dates. It works fine but it just 
ain't pretty.