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sqrt in bash

 
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# 1  
Old 01-24-2011
sqrt in bash
Hi,
i have a the following script:
Code:
#!/bin/bash
a=3
b=9
let "c= b*a"
let "d=sqrt $c "

echo $d

But when i execute the code, it gives me the an error saying:

line 5: let: d=sqrt 27 : syntax error in expression (error token is "27 ")

Can any body tell me what I'm doing wrong?
# 2  
Old 01-24-2011
Because Bash (and most other shells) don't know any mathematical operations or functions beyond the basic five (add, sub, mul, div, mod). If you need higher level functions, use bc or a different scripting language like Perl or Python.
This User Gave Thanks to pludi For This Post:
limadario
# 3  
Old 01-24-2011
Now i have another problem. My bash file looks like this:
Code:
#!/bin/bash
cd /home/dario/Desktop/relatorio/$valor
ls
a=3
b=9
let "c= b*a"
d=$(echo "sqrt($c)" | bc)

echo "$d"

And the result that it gives is the integer of the result, but i want the float result. how can i do this?

Thanks
This User Gave Thanks to limadario For This Post:
blueanindyadas
# 4  
Old 01-24-2011
Code:
d=$(echo "scale=2;sqrt($c)" | bc)

# 5  
Old 01-24-2011
Code:
 a=3
b=6
ruby -e "puts '%.2f' % Math.sqrt($a * $b)"

This User Gave Thanks to kurumi For This Post:
limadario
# 6  
Old 01-24-2011
Kurumi your solution worked perfectly. Thanks
 
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