loading_bar.sh

#!/bin/bash

clear # clears the terminal in the beginning
length=20 # time in seconds to wait before command is executed again
exitcode=0 # exit variable can be set to 1 to exit while loop
updateinterval=1 # update interval of the loading bar in seconds

# Exitcode could be set to 1 if while should end
while [ exitcode != 1 ]
do
    # basic calculation for size of loading bar based on the time with the update interval
    size=`echo "scale=0 ; $length / $updateinterval" | bc`
    # clear the terminal
    clear
    # Header text
    echo "Execute command every $length seconds"
    # Add command here
    # for example
    svn up
    
    # for loop for adding the chars for the loading bbar
    for ((i = 0; i <= size; i++))
    do
        # the output needs a closing bracket and a \r for using the same line everytime
        output="]\r"
        # first for loop for the empty area of the loading bar
        for ((a = 0; a <= size-i; a++))
        do
            # exisiting output will be put back into the output with a extra dot
            output=".$output"
        done
        
        # second for loop for the marked area of the loading bar
        for ((b = size; b >= size-i; b--))
        do
            # exisiting output will be put back into the output with a extra hastag
            output="█$output"
        done
        
        # existing output will be closed with a opening bracket
        output="[$output"
        
        # final echo of the output
        # -ne for using the same line and do not use a linebreak after
        echo -ne $output
        
        # sleep in seconds for the timing of the loading bar
        # Loading bar is based on the length and updateinterval defined above
        # sleep only as long as the updateinterval
        sleep $updateinterval
    done
    # for loop for the loading bar is done here and will be started again with the while
done
# while loop is done here