How to include a timer in Bash Scripting?

Question

Good day! Is there any way to include a timer (timestamp?or whatever term it is) in a script using bash? Like for instance; every 60 seconds, a specific function checks if the internet is down, if it is, then it connects to the wifi device instead and vice versa. In short, the program checks the internet connection from time to time.

Any suggestions/answers will be much appreciated. =)

Answer 1

Blunt version

while sleep 60; do
  if ! check_internet; then
    if is_wifi; then
       set_wired
    else
       set_wifi
    fi
  fi
done

Using the sleep itself as loop condition allows you to break out of the loop by killing the sleep (i.e. if it's a foreground process, ctrl-c will do).

If we're talking minutes or hours intervals, cron will probably do a better job, as Montecristo pointed out.

Answer 2

You may want to do a man cron.

Or if you just have to stick to bash just put the function call inside a loop and sleep 60 inside the iteration.