Floating point calculation in linux shell script

BC is a useful utility/language to do floating point calculation in linux shell script.

it has so many formats, here are two examples,
bc <<< 20+5/2
bc <<< 'scale=4;20+5/2'

here scale=4 means we will consider decimal up to four digits.

another example may be,

echo "scale=4;$a/$b" | bc

details here.

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