Linux Shell Scripting Cookbook - Third Edition

Producing delays in a script

The sleep command will delay a script's execution period of time given in seconds. The following script counts from 0 to 40 seconds using tput and sleep:

#!/bin/bash 
#Filename: sleep.sh 
echo Count: 
tput sc 

# Loop for 40 seconds 
for count in `seq 0 40` 
do 
  tput rc 
  tput ed 
  echo -n $count 
  sleep 1 
done

In the preceding example, a variable steps through the list of numbers generated by the seq command. We use tput sc to store the cursor position. On every loop execution, we write the new count in the terminal by restoring the cursor position using tput rc, and then clearing to the end of the line with tputs ed. After the line is cleared, the script echoes the new value. The sleep command causes the script to delay ...