#!/bin/bash
for i in $(seq $1)
do
echo -n '.'
sleep 1
done
echo
The script prints a dot per second and the number of dots on the screen depending on user's input. What I want to do is that when I press a key (for example, a), the script will run faster like one dot in half a second..so the more I press the same key, the faster it runs.
Use a variable for the duration of the sleep:
duration=1
# ... inside loop:
sleep $duration
# ...
Then each time a call to sleep finishes, have some code to check for new keypresses and alter the value of $duration as needed.
On another note, depending on the version of sleep you have available, it may not support fractional arguments so you might have to use a separate program like usleep.
sleep does work with seconds only. So usleep would be a better choice since it supports microseconds.
sleep supports fractional seconds, so it varies. Anyway I'll add that.