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Bash Floating Number Variables Comparision

 
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# 1  
Old 07-08-2013
Bash Floating Number Variables Comparision
I am trying to compare the floating number variables but i am receiving an error, can you please help what is wrong. Thank you.

Code:
#!/bin/bash

var1=100.25
var2=100.25

if (( $var1 == $var2 )); then
        echo "Matching"
else
        echo "Not Matching"
fi

Error:
Code:
./number.sh: line 6: ((: 100.25 == 100.25 : syntax error: invalid arithmetic operator (error token is ".25 == 100.25 ")
Not Matching

# 2  
Old 07-08-2013
Bash does not support floating point arithmetic. Use ksh93 instead, if possible.
# 3  
Old 07-08-2013
Interesting so there is no other way in bash shell to achieve this other than using korn shell ?
# 4  
Old 07-08-2013
There are many awkward ways to do so. For instance:

Code:
if awk -v VAR1="$VAR1" -v VAR2="$VAR2" 'BEGIN { exit(!(VAR1 == VAR2)); }'
then
...
fi

But ksh93 supports it directly, without external utilities.
This User Gave Thanks to Corona688 For This Post:
Ariean
# 5  
Old 07-08-2013
Code:
export var1="100.25" && export var2="100.25"

[ $var1 == $var2 ] && echo "match" || echo "no match"
match


export var1="100.55" && export var2="100.25"

[ $var1 == $var2 ] && echo "match" || echo "no match"
no match

This User Gave Thanks to in2nix4life For This Post:
Ariean
# 6  
Old 07-08-2013
Or you can use bc - An arbitrary precision calculator language:
Code:
if [ $( echo "$var1 == $var2" | bc -l ) -eq 1 ]
then
        echo "Matching"
else
        echo "Not Matching"
fi

This User Gave Thanks to Yoda For This Post:
Ariean
# 7  
Old 07-08-2013
Quote:
Originally Posted by in2nix4life
Code:
export var1="100.25" && export var2="100.25"

[ $var1 == $var2 ] && echo "match" || echo "no match"
match


export var1="100.55" && export var2="100.25"

[ $var1 == $var2 ] && echo "match" || echo "no match"
no match

This will not work when comparing 100.25 to 100.250
This User Gave Thanks to Corona688 For This Post:
Ariean
 
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