Script help - Dates

[Greg Stark_1]

I have a faxing app that I need to write a simple script to purge the outbound fax entries. The command used is as follows:

faxdbdel -OUTBOUND -to YYMMDD

The user wants to keep 2 weeks worth in the db. I figured I would write a cron script which is called daily to accomplish this, but I'm having some problems trying to load the command with the correct day (DD) of 2 weeks ago. Any ideas?

thanks,
Greg

[Sachin Patel]

Hi Greg,
To get the day of month is
date +%d day of month
date +%a for week day etc..

If you don't mind post your script or part of script which has problem.

Sachin

[Michael Tully]

Hi,

I'm certainly not going to take credit for this, but Mr Stephenson's 'caljd.sh' script will do this job. I'm sure you find it easily by searching, or it may even be posted by Clay himself.

Cheers
~Michael~

[A. Clay Stephenson · Accepted solution]

Hi Greg: This rather cryptic shell line will do the trick:

DAY=$(echo $(caljd.sh -y -s $(caljd.sh -p 14)) | cut -c 3-)
echo "DAY=${DAY}"

The inner caljd.sh returns the Julian Day 14 days ago and the outer caljd.sh says format in YYYY MM DD format (-e) and reove the spaces (-s) to yield YYYYMMDD. The cut then says returns characters 3 to the end of string or YYMMDD - just what you asked for.

See the attached caljd.sh. Caljd.sh -u will give full usage.

[Craig Rants]

I agree, basically Clay's script is the defacto standard for date calculations in this forum.

GL,
C

[Sachin Patel]

Woo nice script Mr. Clay.

Thanks

[Greg Stark_1]

I agree, I wish I had it for some previous scripts.

Thanks,again.

[Greg Stark_1]

Ok, one more question. With the help of caljd.sh I can return the the month of the year from 14 days ago in a 2-digit form. Besides using a long case or if/elsif statement, is there an easy way to convert a 2-digit month to the corresponding 3 letter string?

For instance:
04=Apr

thanks,
Greg

[A. Clay Stephenson]

That's fairly easy too; we just take advantage of the shell's arrays:

#!/usr/bin/sh

MO[01]="Jan"
MO[02]="Feb"
MO[03]="Mar"
MO[04]="Apr"
MO[05]="May"
MO[06]="Jun"
MO[07]="Jul"
MO[08]="Aug"
MO[09]="Sep"
MO[10]="Oct"
MO[11]="Nov"
MO[12]="Dec"

DAY=$(echo $(caljd.sh -y -s $(caljd.sh -p 14)) | cut -c 3-)
echo "DAY=${DAY}"
MONTH=${MO[$(caljd.sh -M $(caljd.sh -p 14))]}
echo "Month=${MONTH}"

[A. Clay Stephenson]

Hi again Greg:

Yet another way to convert 04 to "Apr" although I like the previous method better; it's less obscure.

#!/usr/bin/sh


SMONTH="???JanFebMarAprMayJunJulAugSepOctNovDec"

DAY=$(echo $(caljd.sh -y -s $(caljd.sh -p 14)) | cut -c 3-)
echo "DAY=${DAY}"

NMONTH=$(caljd.sh -M $(caljd.sh -p 14))
OFFSET=$(((${NMONTH} * 3) + 1))
STOP=$((${OFFSET} + 2))
MONTH=$(echo ${SMONTH} | cut -c ${OFFSET}-${STOP})
echo "MONTH=${MONTH}"

[Greg Stark_1]

I think I follow them both, but why all the ?'s in the SMONTH string?

Thank again,
Greg

[A. Clay Stephenson]

Hi Greg:

Without the dummy values for month 0 the offset calculations become offset = ((month - 1) * 3) + 1 - even more messy.

[A. Clay Stephenson]

Okay Greg last time:

Your last question did make me realize that there was a better way still to do the offset into the month string. Use two '?'s and then it is not necessary to subtract 1 so that offset = (month * 3).

#!/usr/bin/sh


SMONTH="??JanFebMarAprMayJunJulAugSepOctNovDec"

DAY=$(echo $(caljd.sh -y -s $(caljd.sh -p 14)) | cut -c 3-)
echo "DAY=${DAY}"

NMONTH=$(caljd.sh -M $(caljd.sh -p 14))
OFFSET=$((${NMONTH} * 3))
STOP=$((${OFFSET} + 2))
MONTH=$(echo ${SMONTH} | cut -c ${OFFSET}-${STOP})
echo "MONTH=${MONTH}"