Most Unix/Linux users will be familiar the sleep command which you can use to delay for the specified number of seconds.  A few years ago I had need for a sleep command which would sleep for a random amount of time, so I came up with some code which as it happens is a nice example of interrupt handling in Unix/Linux.

The code I’ve written to do this random sleep can be freely used but I would like you to leave the reference to this site, http://linuxtech.ie.  It has no external dependencies, so this should compile it:

cc -Wall -O randsleep.c -o randsleep

The two options I use are to warn about any dodgy coding (-Wall) and -O for optimisation (not really an issue here!).

It is used like this:

randsleep [-v] <lower limit> <upper limit>

The -v option will echo the random time it has calculated, e.g:

vger:~(217)+>- randsleep -v 2 7
Sleeping for 3.49 seconds
vger:~(218)+>- randsleep -v 2 7
Sleeping for 5.30 seconds
vger:~(219)+>-