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tech:others:cron_to_schedule_specific_recurring_days [2014/11/15 09:13] (current)
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 +====== Cronjob to schedule specific recurring days ======
 +If you want to run schedule for a certain recurring time such as the 1st Saturday of the month, etc then cron does not have the facility to do that. However the underlying job can have a filter to only trigger for those specific conditions. I have two conditions listed below and the script to go with them.
 +
 +===== Setup cron for 1st, 3rd and 5th weekends =====
 +This script will send a message to my phone Each **Friday** evening at **5:01 pm** on the **odd weekends** to my cell phone.
 +==== Cron Entry ====
 +<​code>​
 +01 17 * * 5 /​home/​xxxxxx/​reminder/​rem1.bash
 +</​code>​
 +
 +==== rem1.bash script ====
 +<code bash>
 +#!/bin/bash
 +# Script to send notification to phone on 1st, 2nd, 3rd Week (Friday as defined in cron)
 +# Get the date number (1-31)
 +TODAYDATE=$(date +%d)
 +# Subtract 1 so 0-6 is 1st week and so on
 +DATEM1=$(($TODAYDATE - 1))
 +# Divide by 7 to get the Week # from 0 to 4 (5 weeks)
 +WEEKNUM=$(($DATEM1 / 7))
 +# Divide by 2 to get odd/even week
 +EVENWEEK=$(($WEEKNUM % 2))
 +#echo "​$TODAYDATE - $EVENWEEK"​
 +#
 +# If Odd week then Send Notification
 +if [ "​$EVENWEEK"​ = "​0"​ ]; then
 +   echo "Odd Friday ..." | /​usr/​bin/​mailx -s "​Message here" "​4445556666@mobile.mycingular.com"​
 +fi
 +#
 +exit
 +</​code>​
 +
 +
 +===== Setup cron for 1st Saturday ​ =====
 +This script will send a message to my phone Each **Saturday** morning at **8:14 am** on the **1st (Sat) weekend** to my cell phone.
 +==== Cron Entry ====
 +<​code>​
 +14 08 * * 6 /​home/​xxxxxx/​reminder/​rem2.bash
 +</​code>​
 +
 +==== rem2.bash script ====
 +<code bash>
 +#!/bin/bash
 +# Script to send notification the 1st sat 
 +# Get the date number (1-31)
 +TODAYDATE=$(date +%d)
 +# Subtract 1 so 0-6 is 1st week and so on
 +DATEM1=$(($TODAYDATE - 1))
 +# Divide by 7 to get the Week # from 0 to 4 (5 weeks)
 +WEEKNUM=$(($DATEM1 / 7))
 +# If 1st week then Send Notification
 +if [ "​$WEEKNUM"​ = "​0"​ ]; then
 +   echo "1st Sat" | /​usr/​bin/​mailx -s "​message"​ "​4445556666@mobile.mycingular.com"​
 +fi
 +#
 +exit
 +</​code>​
 +
 +===== Other considerations =====
 +For the 1st Saturday weekend my initial "​reaction"​ was to just do a crontab such as this:
 +<​code>​
 +14 08 1-7 * 6 /​home/​xxxxxx/​reminder/​rem2.bash
 +</​code>​
 +However cron interprets this as trigger on days 1-7 **plus** Saturdays! So that won't quite work.
 +
 +This has been very helpful to do notification for odd, even weekends, specific week such as 1st, 2nd, 3rd, 4th or 5th weekends and specific day of a specific weekend such as 1st Saturday, 3rd Thursday, etc.
 +
  

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