bc -l pi=3.1

1cpuer

bc -l
scale=8;a(1)*4
3.14159264
quit

a(1) 是设么？

Shell_HAT

# echo "scale=8; 4*a(1)" | bc -l
3.14159264

christmas1102

command line>>> man bc

MATH LIBRARY
       If bc is invoked with the -l option, a math library is preloaded and the default scale is set to 20.   The math functions will calculate  their  results  to  the
       scale set at the time of their call.  The math library defines the following functions:

       s (x)  The sine of x, x is in radians.
       c (x)  The cosine of x, x is in radians.
       a (x)  The arctangent of x, arctangent returns radians.
       l (x)    The natural logarithm of x.
       e (x)    The exponential function of raising e to the value x.
       j (n,x)    The Bessel function of integer order n of x.