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A quick example of what I want using bash scripting:

#!/bin/bash
echo "Insert the price you want to calculate:"
read float
echo "This is the price without taxes:"
echo "scale=2; $float/1.18" |bc -l
read -p "Press any key to continue..."
bash scriptname.sh

Assuming that the price is: 48.86 The answer will be:41.406779661 (41.40 actually because I'm using scale=2;)

My Question is: How I round the second decimal to show the answer in this way?: 41.41

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I find it weird because "printf "%0.2f\n" 41.445" does now work but "printf "%0.2f\n" 41.435 and printf "%0.2f\n" 41.455" do. Even your own case works (On 12.04) but not with the .445 –  Luis Alvarado Aug 24 '12 at 16:44
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2 Answers

up vote 6 down vote accepted

A bash round function:

round()
{
echo $(printf %.$2f $(echo "scale=$2;(((10^$2)*$1)+0.5)/(10^$2)" | bc))
};

Used in your code example:

#!/bin/bash
# the function "round()" was taken from 
# http://stempell.com/2009/08/rechnen-in-bash/

# the round function:
round()
{
echo $(printf %.$2f $(echo "scale=$2;(((10^$2)*$1)+0.5)/(10^$2)" | bc))
};

echo "Insert the price you want to calculate:"
read float
echo "This is the price without taxes:"
#echo "scale=2; $float/1.18" |bc -l
echo $(round $float/1.18 2);
read -p "Press any key to continue..."

Good luck :o)

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1  
Right now, this is the nicest way to do it, thanks for your knowledge. –  blackedx Aug 24 '12 at 16:51
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Pure bash rounding:

echo "23.49" | awk '{printf("%d\n",$1 + 0.5)}'

If you have python you can use something like this:

echo "4.678923" | python -c "print round(float(raw_input()))"

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Thanks for the tip but it doesn't solve what I need. I have to do it just by using bash... –  blackedx Aug 24 '12 at 14:39
    
The python command is more readable and good for quick scripts. Also supports arbitrary digit rounding by adding e.g. ", 3" to the round function. Thanks –  Jordan Trudgett Nov 13 '13 at 2:07
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