topic Re: scripting cron job in Operating System - Linux

scripting cron job

Dan Matlock_1 — Wed, 30 Nov 2005 17:27:46 GMT

Does anyone have a snippet of code to ID the last sunday of each month or first saturday of each month? I basically have servers that I want to reboot during those times, and need a wrapper script to launch shutdown. Bi-weekly finding even/odd week was easy, but look for creative/effective ideas on the once per month stuff.

Re: scripting cron job

A. Clay Stephenson — Wed, 30 Nov 2005 17:51:16 GMT

I don't like the idea of rebooting like this but:

The easy way to do this is run your script each Sunday and have it decide if it is the 1st Sunday and execute or simply exit if not.

Install the attached caljd.sh in /usr/local/bin

Your script which is executed by cron every Sunday at whatever time you like looks like this:

#!/usr/bin/sh

export PATH=${PATH}:/usr/local/bin

typeset -i STAT=0
if [[ $(caljd.sh -N) -eq 1 ]]
then
echo "1st Sunday; do your thing"
# set the value of ${STAT}
fi
exit ${STAT}

---------------------------------------

The last Saturday is similar wee look at the month today and 7 days hence and if they differ, today is the last Saturday:

export PATH=${PATH}:/usr/local/bin

typeset -i STAT=0
if [[ $(caljd.sh -M) -ne $(caljd.sh -M -n 7) ]]
then
echo "Last Saturday; do your thing"
# set the value of ${STAT}
fi
exit ${STAT}

Invoke as caljd.sh -u for many examples.

Re: scripting cron job

Muthukumar_5 — Thu, 01 Dec 2005 02:56:47 GMT

To get last sunday of the month then,

#!/bin/sh
#sunday.sh
# /usr/bin/sunday.sh

if [[ $(date +'%d') -eq $(cal | cut -b 1,2 | grep -v '^$' | tail -1) ]]
then
# You can do reboot. It is not recommeded anway
shutdown -r now
fi

# END
exit 0
############

To execute shutdown on first saturday of the month then,

#!/bin/sh
#saturday.sh
# /usr/bin/saturday.sh

if [[ $(date +'%d') -eq $(cal | cut -b 19,20 | awk '{ if ( $1 ~ "S") { getline;print; }}') ]]
then
# You can do reboot. It is not recommeded anway
shutdown -r now
fi

# END
exit 0
############

Put this script in cron tab as,

0 7 * * * /usr/bin/sunday.sh 1>/dev/null 2>&1

it will execute every day morning 7'o clock.. And do reboot on the last sunday or saturday.

Change sunday.sh to saturday.sh to execute on first saturday.

hth.