random sleep

[luishi07]

Does anyone here knows how to make a random sleep of a maximum desired duration?.
for example i want execute wget after a time that may vary from 0 to 2 hours
thanks a lot!

[luishi07]

When i do this in a terminal window it works fine:
value=$RANDOM
echo $value

but in a script it does not works WHYYYYY!!!!???????

#!/bin/bash

value=$RANDOM
echo $value


PLEASE HELP!!!

[vsemaska]

It doesn't work in a script? Sure you don't have a typo because it works for me. This is what I came up with:

value=$RANDOM
ct=`echo "scale=0; $value / 4.5509722" | bc`
sleep $ct

RANDOM returns a no. between 0 and 32767. The 4.5509722 scales it down to 0 and 7200 (0 to 2 hours).

[luishi07]

Please i've tried what you suggested, in a term window it works but in a .sh file it does not.
Whats going on????

[luishi07]

Please help im desperate!

[vsemaska]

Post your script as an attachment.

[luishi07]

Its a copy paste of your reply

[luishi07]

sorry didn't send it in last reply here it is

[vsemaska]

Don't know what's happening. What the bash manpage says is:

If RANDOM is unset, it loses its special properties, even if it is subsequently
reset.

Sounds like RANDOM is being unset for some reason but I don't know why.


Another way without using RANDOM is this:

ct=`dd bs=200 count=1 < /dev/urandom | tr -cd '[:digit:]' | head -c4`
# Produce a random number from 0 to 9999.

if [ "$ct" = "" ]; then ct=0; fi
# Assume 0 if urandom didn't return any digits.

ct=`echo "scale=0; $ct / 1.38875" | bc`
# Scale down to 7200 seconds (2 hours).

Gotta go. Hope this helps.

[luishi07]

This works but im really surprised, the previous commands do work but only in the terminal window and don't inside a bash (.sh) file.
Thanks a lot for all your help this is thing was crucial for me.