Shell Programming and Scripting

If I want to run a process every 30 mins except for 3-4 where I want to run
every 5 mins I know I can do this with 3 entries.

Code:

 
30 5-23 * * * "echo "Hello"
30 0-3 * * * "echo "Hello"
5,10,15,20,25,30,35,40,45,50,55 3-4, * * * "echo Hello"

Can this be done with less entries

I think that is as simple as that solution gets. I'll keep it in the corner of my mind and come back if anything pops up.

Note: echo hello is NOT something you would crontab - I'm assuming you know that.
crontab processes do not have a terminal, for example.

one way move timing inside the script you evoke in crontab -

Code:

#!/bin/bash
# this file == /path/to/timer.sh
hour=$(date +%H)
minute=$(date +%M)
if [ $hour = "03"  || $hour = "05" || $minute = "30" ] ; then
 #  /path/to/your/script    i.e., put your code here
fi

Code:

0 0,5,10,15,20,25,30,35,40,45,50,55 * * * /path/to/timer.sh

A script to evoke his task from cron is not more elegant, it uses more memory and just isn't simplification but outsourcing to bash.

These crons do not process every 30 mins. They process every hour. All the lines which contain three double-quote characters are syntax errors.
Please clarify.

This cron does not process every 5 mins between 3 and 4. More like 3 and 5 (but missing out exact hours).
The extra comma in "3-4," makes that line a syntax error too.
Please clarify.


Sorry, but you are asking us to simplify something which does not conform to specification at all. Also, all three lines contain syntax errors.


To answer your original question. Yes, it can be done with TWO entries (and no special Shell or whatever).
One cron to run every 30 mins and one cron to fill in the extra 5 mins intervals.

Code:

0,30 0-23 * * * echo "Hello"
5,10,15,20,25,35,40,45,50,55 3 * * * echo "Hello"