Unix/Linux Go Back    

OpenSolaris 2009.06 - man page for bc (opensolaris section 1)

Linux & Unix Commands - Search Man Pages
Man Page or Keyword Search:   man
Select Man Page Set:       apropos Keyword Search (sections above)

bc(1)					  User Commands 				    bc(1)

       bc - arbitrary precision arithmetic language

       /usr/bin/bc [-c] [-l] [file]...

       /usr/xpg6/bin/bc [-c] [-l] [file]...

       The bc utility implements an arbitrary precision calculator. It takes input from any files
       given, then reads from the standard input. If the standard input and standard output to bc
       are  attached to a terminal, the invocation of bc is  interactive, causing behavioral con-
       straints described in the following sections. bc processes a language that resembles C and
       is  a  preprocessor  for  the  desk  calculator program dc, which it invokes automatically
       unless the -c option is specified. In this case the dc input is sent to the standard  out-
       put instead.

       The syntax for  bc programs is as follows:

       L    Means a letter a-z,

       E    Means  an  expression:  a  (mathematical  or logical) value, an operand  that takes a
	    value, or a combination of operands and operators that evaluates to a value,

       S    Means a statement.

       Enclosed in /* and */.

   Names (Operands)
	 Simple variables: L.
	 Array elements: L [ E ] (up to BC_DIM_MAX dimensions).
	 The words ibase, obase (limited to BC_BASE_MAX), and scale (limited to BC_SCALE_MAX).

   Other Operands
       Arbitrarily long numbers with optional sign and	decimal  point.  Strings  of  fewer  than
       BC_STRING_MAX characters, between double quotes ("). ( E )

       sqrt ( E )	    Square root

       length ( E )	    Number of significant decimal digits.

       scale ( E )	    Number of digits right of decimal point.

       L ( E , ... , E )

       +   -   *   /   %   ^

	   (% is remainder; ^ is power)

       ++   --

	   (prefix and postfix; apply to names)

       ==   <=	 >=   !=   <   >

       =   =+	=-   =*   =/   =%   =^

	 { S ;... ; S }
	 if ( E ) S
	 while ( E ) S
	 for ( E ; E ; E ) S
	 null statement


   Function Definitions
	 define L ( L ,..., L ) {
	      auto L ,..., L
	      S ;... S
	      return ( E )

   Functions in -l Math Library
       s(x)	 sine

       c(x)	 cosine

       e(x)	 exponential

       l(x)	 log

       a(x)	 arctangent

       j(n,x)	 Bessel function

       All function arguments are passed by value.

       The  value  of a statement that is an expression is printed unless the main operator is an
       assignment. Either semicolons or new-lines may separate statements.  Assignment	to  scale
       influences  the	number of digits to be retained on arithmetic operations in the manner of
       dc. Assignments to ibase or obase set the input and output number radix respectively.

       The same letter may be used as an array, a function, and a simple variable simultaneously.
       All variables are global to the program. auto variables are stacked during function calls.
       When using arrays as function arguments or defining them  as  automatic	variables,  empty
       square brackets must follow the array name.

       The following operands are supported:

       -c    Compiles only. The output is dc commands that are sent to the standard output.

       -l    Defines the math functions and initializes scale to 20, instead of the default zero.

       -l    Defines the math functions and initializes scale to 20, instead of the default zero.
	     All math results have the scale of 20.

       The following operands are supported:

       file    A pathname of a text file containing bc program statements.  After  all	cases  of
	       file have been read, bc reads the standard input.

       Example 1 Setting the precision of a variable

       In  the	shell, the following assigns an approximation of the first ten digits of n to the
       variable x:

	 x=$(printf "%s\n" 'scale = 10; 104348/33215' | bc)

       Example 2 Defining a computing function

       Defines a function to compute an approximate value of the exponential function:

	 scale = 20
	 define e(x){
	      auto a, b, c, i, s
	      a = 1
	      b = 1
	      s = 1
	      for(i=1; 1==1; i++){
		   a = a*x
		   b = b*i
		   c = a/b
		   if(c == 0) return(s)
		   s = s+c

       Example 3 Printing the approximate values of the function

       Prints approximate values of the exponential function of the first ten integers:

	 for(i=1; i<=10; i++) e(i)


	 for (i = 1; i <= 10; ++i) {	     e(i) }

       See environ(5) for descriptions of the following environment  variables	that  affect  the
       execution of bc: LANG, LC_ALL, LC_CTYPE, LC_MESSAGES, and NLSPATH.

       The following exit values are returned:

       0	      All input files were processed successfully.

       unspecified    An error occurred.

       /usr/lib/lib.b		mathematical library

       /usr/include/limits.h	to define BC_ parameters

       See attributes(5) for descriptions of the following attributes:

       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       |Availability		     |SUNWesu			   |
       |Interface Stability	     |Standard			   |

       dc(1), awk(1), attributes(5), environ(5), standards(5)

       The bc command does not recognize the logical operators && and ||.

       The for statement must have all three expressions (E's).

SunOS 5.11				   29 Aug 2003					    bc(1)
Unix & Linux Commands & Man Pages : ©2000 - 2018 Unix and Linux Forums

All times are GMT -4. The time now is 05:37 PM.