Coordinate format
degrees minutes seconds: 40° 26′ 46″ N 79° 58′ 56″ W
degrees decimal minutes: 40° 26.767′ N 79° 58.933′ W
decimal degrees: 40.446° N 79.982° W

#convertion
#degrees decimal minutes to decimal degrees
degrees + (decimal_minutes/60)

#example
ddm=40° 26.767′ N 79° 58.933′ W
dd=40+(26.767/60)

#BASH
echo "40+(26.767/60)"|bc -l
#limit decimal spaces
echo "scale=6;40+(26.767/60)"|bc -l