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Diffstat (limited to 'usr.bin/bc/bc.1')
| -rw-r--r-- | usr.bin/bc/bc.1 | 396 |
1 files changed, 396 insertions, 0 deletions
diff --git a/usr.bin/bc/bc.1 b/usr.bin/bc/bc.1 new file mode 100644 index 0000000..8fe21c6 --- /dev/null +++ b/usr.bin/bc/bc.1 @@ -0,0 +1,396 @@ +.\" $FreeBSD$ +.\" $OpenBSD: bc.1,v 1.25 2010/01/02 19:48:56 schwarze Exp $ +.\" +.\" Copyright (C) Caldera International Inc. 2001-2002. +.\" All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code and documentation must retain the above +.\" copyright notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" 3. All advertising materials mentioning features or use of this software +.\" must display the following acknowledgement: +.\" This product includes software developed or owned by Caldera +.\" International, Inc. +.\" 4. Neither the name of Caldera International, Inc. nor the names of other +.\" contributors may be used to endorse or promote products derived from +.\" this software without specific prior written permission. +.\" +.\" USE OF THE SOFTWARE PROVIDED FOR UNDER THIS LICENSE BY CALDERA +.\" INTERNATIONAL, INC. AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR +.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES +.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. +.\" IN NO EVENT SHALL CALDERA INTERNATIONAL, INC. BE LIABLE FOR ANY DIRECT, +.\" INDIRECT INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES +.\" (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR +.\" SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, +.\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING +.\" IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE +.\" POSSIBILITY OF SUCH DAMAGE. +.\" +.\" @(#)bc.1 6.8 (Berkeley) 8/8/91 +.\" +.Dd January 22, 2010 +.Dt BC 1 +.Os +.Sh NAME +.Nm bc +.Nd arbitrary-precision arithmetic language and calculator +.Sh SYNOPSIS +.Nm bc +.Op Fl chlqv +.Op Fl e Ar expression +.Op Ar file ... +.Sh DESCRIPTION +.Nm +is an interactive processor for a language which resembles +C but provides unlimited precision arithmetic. +It takes input from any expressions on the command line and +any files given, then reads the standard input. +.Pp +Options available: +.Bl -tag -width Ds +.It Fl c +.Nm +is actually a preprocessor for +.Xr dc 1 , +which it invokes automatically, unless the +.Fl c +.Pq compile only +option is present. +In this case the generated +.Xr dc 1 +instructions are sent to the standard output, +instead of being interpreted by a running +.Xr dc 1 +process. +.It Fl e Ar expression , Fl Fl expression Ar expression +Evaluate +.Ar expression . +If multiple +.Fl e +options are specified, they are processed in the order given, +separated by newlines. +.It Fl h , Fl Fl help +Prints usage information. +.It Fl l , Fl Fl mathlib +Allow specification of an arbitrary precision math library. +The definitions in the library are available to command line +expressions. +Synonym for +.Fl l . +.It Fl v , Fl Fl version +Prints version information. +.El +.Pp +The syntax for +.Nm +programs is as follows: +.Sq L +means letter a-z; +.Sq E +means expression; +.Sq S +means statement. +As a non-portable extension, it is possible to use long names +in addition to single letter names. +A long name is a sequence starting with a lowercase letter +followed by any number of lowercase letters and digits. +The underscore character +.Pq Sq _ +counts as a letter. +.Pp +Comments +.Bd -unfilled -offset indent -compact +are enclosed in /* and */ +are enclosed in # and the next newline +.Ed +.Pp +The newline is not part of the line comment, +which in itself is a non-portable extension. +.Pp +Names +.Bd -unfilled -offset indent -compact +simple variables: L +array elements: L [ E ] +The words `ibase', `obase', and `scale' +The word `last' or a single dot +.Ed +.Pp +Other operands +.Bd -unfilled -offset indent -compact +arbitrarily long numbers with optional sign and decimal point +( E ) +sqrt ( E ) +length ( E ) number of significant decimal digits +scale ( E ) number of digits right of decimal point +L ( E , ... , E ) +.Ed +.Pp +The sequence +.Sq \e<newline><whitespace> +is ignored within numbers. +.Pp +Operators +.Pp +The following arithmetic and logical operators can be used. +The semantics of the operators is the same as in the C language. +They are listed in order of decreasing precedence. +Operators in the same group have the same precedence. +.Bl -column -offset indent "= += \-= *= /= %= ^=" "Associativity" \ +"multiply, divide, modulus" +.It Sy "Operator" Ta Sy "Associativity" Ta Sy "Description" +.It "++ \-\-" Ta "none" Ta "increment, decrement" +.It "\-" Ta "none" Ta "unary minus" +.It "^" Ta "right" Ta "power" +.It "* / %" Ta "left" Ta "multiply, divide, modulus" +.It "+ \-" Ta "left" Ta "plus, minus" +.It "= += -= *= /= %= ^=" Ta "right" Ta "assignment" +.It "== <= >= != < >" Ta "none" Ta "relational" +.It "!" Ta "none" Ta "boolean not" +.It "&&" Ta "left" Ta "boolean and" +.It "||" Ta "left" Ta "boolean or" +.El +.Pp +Note the following: +.Bl -bullet -offset indent +.It +The relational operators may appear in any expression. +The +.St -p1003.2 +standard only allows them in the conditional expression of an +.Sq if , +.Sq while +or +.Sq for +statement. +.It +The relational operators have a lower precedence than the assignment +operators. +This has the consequence that the expression +.Sy a = b < c +is interpreted as +.Sy (a = b) < c , +which is probably not what the programmer intended. +.It +In contrast with the C language, the relational operators all have +the same precedence, and are non-associative. +The expression +.Sy a < b < c +will produce a syntax error. +.It +The boolean operators (!, && and ||) are non-portable extensions. +.It +The boolean not +(!) operator has much lower precedence than the same operator in the +C language. +This has the consequence that the expression +.Sy !a < b +is interpreted as +.Sy !(a < b) . +Prudent programmers use parentheses when writing expressions involving +boolean operators. +.El +.Pp +Statements +.Bd -unfilled -offset indent -compact +E +{ S ; ... ; S } +if ( E ) S +if ( E ) S else S +while ( E ) S +for ( E ; E ; E ) S +null statement +break +continue +quit +a string of characters, enclosed in double quotes +print E ,..., E +.Ed +.Pp +A string may contain any character, except double quote. +The if statement with an else branch is a non-portable extension. +All three E's in a for statement may be empty. +This is a non-portable extension. +The continue and print statements are also non-portable extensions. +.Pp +The print statement takes a list of comma-separated expressions. +Each expression in the list is evaluated and the computed +value is printed and assigned to the variable `last'. +No trailing newline is printed. +The expression may also be a string enclosed in double quotes. +Within these strings the following escape sequences may be used: +.Sq \ea +for bell (alert), +.Sq \eb +for backspace, +.Sq \ef +for formfeed, +.Sq \en +for newline, +.Sq \er +for carriage return, +.Sq \et +for tab, +.Sq \eq +for double quote and +.Sq \e\e +for backslash. +Any other character following a backslash will be ignored. +Strings will not be assigned to `last'. +.Pp +Function definitions +.Bd -unfilled -offset indent +define L ( L ,..., L ) { + auto L, ... , L + S; ... S + return ( E ) +} +.Ed +.Pp +As a non-portable extension, the opening brace of the define statement +may appear on the next line. +The return statement may also appear in the following forms: +.Bd -unfilled -offset indent +return +return () +return E +.Ed +.Pp +The first two are equivalent to the statement +.Dq return 0 . +The last form is a non-portable extension. +Not specifying a return statement is equivalent to writing +.Dq return (0) . +.Pp +Functions available in the math library, which is loaded by specifying the +.Fl l +flag on the command line +.Pp +.Bl -tag -width j(n,x) -offset indent -compact +.It s(x) +sine +.It c(x) +cosine +.It e(x) +exponential +.It l(x) +log +.It a(x) +arctangent +.It j(n,x) +Bessel function +.El +.Pp +All function arguments are passed by value. +.Pp +The value of a statement that is an expression is printed +unless the main operator is an assignment. +The value printed is assigned to the special variable `last'. +This is a non-portable extension. +A single dot may be used as a synonym for `last'. +Either semicolons or newlines may separate statements. +Assignment to +.Ar scale +influences the number of digits to be retained on arithmetic +operations in the manner of +.Xr dc 1 . +Assignments to +.Ar ibase +or +.Ar obase +set the input and output number radix respectively. +.Pp +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 pushed down during function calls. +When using arrays as function arguments +or defining them as automatic variables, +empty square brackets must follow the array name. +.Pp +For example +.Bd -literal -offset indent +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 + } +} +.Ed +.Pp +defines a function to compute an approximate value of +the exponential function and +.Pp +.Dl for(i=1; i<=10; i++) e(i) +.Pp +prints approximate values of the exponential function of +the first ten integers. +.Bd -literal -offset indent +$ bc -l -e 'scale = 500; 2 * a(2^10000)' -e quit +.Ed +.Pp +prints an approximation of pi. +.Sh FILES +.Bl -tag -width /usr/share/misc/bc.library -compact +.It Pa /usr/share/misc/bc.library +math library, read when the +.Fl l +option is specified on the command line. +.El +.Sh SEE ALSO +.Xr dc 1 +.Pp +"BC \- An Arbitrary Precision Desk-Calculator Language", +.Pa /usr/share/doc/usd/06.bc/ . +.Sh STANDARDS +The +.Nm +utility is compliant with the +.St -p1003.1-2008 +specification. +.Pp +The flags +.Op Fl ce +are extensions to that specification. +.Sh HISTORY +The +.Nm +command first appeared in +.At v6 . +A complete rewrite of the +.Nm +command first appeared in +.Ox 3.5 . +.Sh AUTHORS +.An -nosplit +The original version of the +.Nm +command was written by +.An Robert Morris +and +.An Lorinda Cherry . +The current version of the +.Nm +utility was written by +.An Otto Moerbeek . +.Sh BUGS +.Ql Quit +is interpreted when read, not when executed. +.Pp +Some non-portable extensions, as found in the GNU version of the +.Nm +utility are not implemented (yet). |
