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I have a scenario where I am taking difference of two numbers.

Then the calculated difference needs to be checked within a range.
If it lie within that range then display status as success, else display failure.

Below is my code

Range = -1 to 1

var1=12.23
var2=13.23

diff=$(echo "($var1-$var2)"| bc -l)
echo $diff

if [ "$diff" -ge -1 ] && [ "$diff" -le 1 ]; then
        echo "$diff" "success"
else
   echo "Not within range -1 to 1"
   echo "Failure"
fi

Error getting like below

script.sh: 8: [: Illegal number: -1.00
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5
  • 1
    The shell only does integer arithmetics and tests against integers. See e.g. How to do integer & float calculations, in bash or other languages/frameworks? You may want to call bc or some other tool to calculate the value of ($var1 - $var2) > 1 (etc.) instead and use the boolean value of that in your script. Commented Feb 26, 2020 at 8:13
  • @Kusalananda can you write code for me which work | how to resolve this error | i have ubuntu Commented Feb 26, 2020 at 8:17
  • @Kusalananda the calculated difference i need to check within range of -1 to 1. If the difference falls under this range i need success status as 1 or display as 0 Commented Feb 26, 2020 at 8:19
  • @Kusalananda 1 = success and 0 = Fail Commented Feb 26, 2020 at 8:20
  • There is an error in line one. Only post code that you have run. Commented Feb 26, 2020 at 10:17

2 Answers 2

Reset to default
1

If you want to play with awk you can use script like:

var1=12.23
var2=13.23
echo |awk -v v1=$var1 -v v2=$var2 '{diff=v1-v2;if(diff >= -1 && diff <=1) print diff " success" ;else printf "%s not within range [-1,1]\nFailure\n", diff }'
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3
  • code not working Commented Feb 26, 2020 at 9:20
  • @techvikky, now should work Commented Feb 26, 2020 at 9:22
  • 1
    code working as expected Commented Feb 26, 2020 at 10:44
1

The shell can't compare strings that represent floating point values in arithmetic contexts. You can however use bc to evaluate a boolean (integer) value that you can use in the shell:

#!/bin/bash

val1=12.23
val2=13.23

difference=$( bc -l <<<"$val1 - $val2" )
range_ok=$( bc -l <<<"$difference >= -1 && $difference <= 1" )

if [ "$range_ok" -ne 0 ]; then
        printf '%s success\n' "$difference"
else
        printf '%s not within range [-1,1]\n' "$difference"
        echo "Failure"
fi
Improve this answer
5
  • let me check the code does it full my requirement or not Commented Feb 26, 2020 at 8:43
  • this test case fails : if var1=12 and var2=13 result = -1 ..even if it gives equal to -1 the script should display success and vice versa Commented Feb 26, 2020 at 9:05
  • range_ok=$( bc -l <<<"$difference > -1" && "$difference < 1" && "$difference == 1" && "$difference == -1" ) Commented Feb 26, 2020 at 9:15
  • @techvikky The code I posted does that correctly already. Note that I'm using >= and <=. Commented Feb 26, 2020 at 9:24
  • code is working as expected Commented Feb 26, 2020 at 10:44

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