bc(1) General Commands Manual bc(1)
NAME
bc - An arbitrary precision calculator language
SYNTAX
bc [ -hlwsqv ] [long-options] [ file ... ]
DESCRIPTION
bc is a language that supports arbitrary precision numbers with interac-
tive execution of statements. There are some similarities in the syntax
to the C programming language. A standard math library is available by
command line option. If requested, the math library is defined before
processing any files. bc starts by processing code from all the files
listed on the command line in the order listed. After all files have
been processed, bc reads from the standard input. All code is executed
as it is read. (If a file contains a command to halt the processor, bc
will never read from the standard input.)
This version of bc contains several extensions beyond traditional bc im-
plementations and the POSIX draft standard. Command line options can
cause these extensions to print a warning or to be rejected. This docu-
ment describes the language accepted by this processor. Extensions will
be identified as such.
OPTIONS
-h, --help
Print the usage and exit.
-i, --interactive
Force interactive mode.
-l, --mathlib
Define the standard math library.
-w, --warn
Give warnings for extensions to POSIX bc.
-s, --standard
Process exactly the POSIX bc language.
-q, --quiet
Do not print the normal GNU bc welcome.
-v, --version
Print the version number and copyright and quit.
NUMBERS
The most basic element in bc is the number. Numbers are arbitrary pre-
cision numbers. This precision is both in the integer part and the
fractional part. All numbers are represented internally in decimal and
all computation is done in decimal. (This version truncates results
from divide and multiply operations.) There are two attributes of num-
bers, the length and the scale. The length is the total number of deci-
mal digits used by bc to represent a number and the scale is the total
number of decimal digits after the decimal point. For example:
.000001 has a length of 6 and scale of 6.
1935.000 has a length of 7 and a scale of 3.
VARIABLES
Numbers are stored in two types of variables, simple variables and ar-
rays. Both simple variables and array variables are named. Names begin
with a letter followed by any number of letters, digits and underscores.
All letters must be lower case. (Full alpha-numeric names are an exten-
sion. In POSIX bc all names are a single lower case letter.) The type
of variable is clear by the context because all array variable names
will be followed by brackets ([]).
There are four special variables, scale, ibase, obase, and last. scale
defines how some operations use digits after the decimal point. The de-
fault value of scale is 0. ibase and obase define the conversion base
for input and output numbers. The default for both input and output is
base 10. last (an extension) is a variable that has the value of the
last printed number. These will be discussed in further detail where
appropriate. All of these variables may have values assigned to them as
well as used in expressions.
COMMENTS
Comments in bc start with the characters /* and end with the characters
*/. Comments may start anywhere and appear as a single space in the in-
put. (This causes comments to delimit other input items. For example,
a comment can not be found in the middle of a variable name.) Comments
include any newlines (end of line) between the start and the end of the
comment.
To support the use of scripts for bc, a single line comment has been
added as an extension. A single line comment starts at a # character
and continues to the next end of the line. The end of line character is
not part of the comment and is processed normally.
EXPRESSIONS
The numbers are manipulated by expressions and statements. Since the
language was designed to be interactive, statements and expressions are
executed as soon as possible. There is no "main" program. Instead,
code is executed as it is encountered. (Functions, discussed in detail
later, are defined when encountered.)
A simple expression is just a constant. bc converts constants into in-
ternal decimal numbers using the current input base, specified by the
variable ibase. (There is an exception in functions.) The legal values
of ibase are 2 through 36. (Bases greater than 16 are an extension.) As-
signing a value outside this range to ibase will result in a value of 2
or 36. Input numbers may contain the characters 0–9 and A–Z. (Note:
They must be capitals. Lower case letters are variable names.) Single
digit numbers always have the value of the digit regardless of the value
of ibase. (i.e. A = 10.) For multi-digit numbers, bc changes all input
digits greater or equal to ibase to the value of ibase-1. This makes
the number ZZZ always be the largest 3 digit number of the input base.
Full expressions are similar to many other high level languages. Since
there is only one kind of number, there are no rules for mixing types.
Instead, there are rules on the scale of expressions. Every expression
has a scale. This is derived from the scale of original numbers, the
operation performed and in many cases, the value of the variable scale.
Legal values of the variable scale are 0 to the maximum number repre-
sentable by a C integer.
In the following descriptions of legal expressions, "expr" refers to a
complete expression and "var" refers to a simple or an array variable.
A simple variable is just a
name
and an array variable is specified as
name[expr]
Unless specifically mentioned the scale of the result is the maximum
scale of the expressions involved.
- expr The result is the negation of the expression.
++ var The variable is incremented by one and the new value is the re-
sult of the expression.
-- var The variable is decremented by one and the new value is the re-
sult of the expression.
var ++
The result of the expression is the value of the variable and
then the variable is incremented by one.
var -- The result of the expression is the value of the variable and
then the variable is decremented by one.
expr + expr
The result of the expression is the sum of the two expressions.
expr - expr
The result of the expression is the difference of the two expres-
sions.
expr * expr
The result of the expression is the product of the two expres-
sions.
expr / expr
The result of the expression is the quotient of the two expres-
sions. The scale of the result is the value of the variable
scale.
expr % expr
The result of the expression is the "remainder" and it is com-
puted in the following way. To compute a%b, first a/b is com-
puted to scale digits. That result is used to compute a-(a/b)*b
to the scale of the maximum of scale+scale(b) and scale(a). If
scale is set to zero and both expressions are integers this ex-
pression is the integer remainder function.
expr ^ expr
The result of the expression is the value of the first raised to
the second. The second expression must be an integer. (If the
second expression is not an integer, a warning is generated and
the expression is truncated to get an integer value.) The scale
of the result is scale if the exponent is negative. If the expo-
nent is positive the scale of the result is the minimum of the
scale of the first expression times the value of the exponent and
the maximum of scale and the scale of the first expression.
(e.g. scale(a^b) = min(scale(a)*b, max( scale, scale(a))).) It
should be noted that expr^0 will always return the value of 1.
( expr )
This alters the standard precedence to force the evaluation of
the expression.
var = expr
The variable is assigned the value of the expression.
var <op>= expr
This is equivalent to "var = var <op> expr" with the exception
that the "var" part is evaluated only once. This can make a dif-
ference if "var" is an array.
Relational expressions are a special kind of expression that always
evaluate to 0 or 1, 0 if the relation is false and 1 if the relation is
true. These may appear in any legal expression. (POSIX bc requires
that relational expressions are used only in if, while, and for state-
ments and that only one relational test may be done in them.) The rela-
tional operators are
expr1 < expr2
The result is 1 if expr1 is strictly less than expr2.
expr1 <= expr2
The result is 1 if expr1 is less than or equal to expr2.
expr1 > expr2
The result is 1 if expr1 is strictly greater than expr2.
expr1 >= expr2
The result is 1 if expr1 is greater than or equal to expr2.
expr1 == expr2
The result is 1 if expr1 is equal to expr2.
expr1 != expr2
The result is 1 if expr1 is not equal to expr2.
Boolean operations are also legal. (POSIX bc does NOT have boolean op-
erations). The result of all boolean operations are 0 and 1 (for false
and true) as in relational expressions. The boolean operators are:
!expr The result is 1 if expr is 0.
expr && expr
The result is 1 if both expressions are non-zero.
expr || expr
The result is 1 if either expression is non-zero.
The expression precedence is as follows: (lowest to highest)
|| operator, left associative
&& operator, left associative
! operator, nonassociative
Relational operators, left associative
Assignment operator, right associative
+ and - operators, left associative
*, / and % operators, left associative
^ operator, right associative
unary - operator, nonassociative
++ and -- operators, nonassociative
This precedence was chosen so that POSIX compliant bc programs will run
correctly. This will cause the use of the relational and logical opera-
tors to have some unusual behavior when used with assignment expres-
sions. Consider the expression:
a = 3 < 5
Most C programmers would assume this would assign the result of "3 < 5"
(the value 1) to the variable "a". What this does in bc is assign the
value 3 to the variable "a" and then compare 3 to 5. It is best to use
parenthesis when using relational and logical operators with the assign-
ment operators.
There are a few more special expressions that are provided in bc. These
have to do with user defined functions and standard functions. They all
appear as "name(parameters)". See the section on functions for user de-
fined functions. The standard functions are:
length ( expression )
The value of the length function is the number of significant
digits in the expression.
read ( )
The read function (an extension) will read a number from the
standard input, regardless of where the function occurs. Be-
ware, this can cause problems with the mixing of data and program
in the standard input. The best use for this function is in a
previously written program that needs input from the user, but
never allows program code to be input from the user. The value
of the read function is the number read from the standard input
using the current value of the variable ibase for the conversion
base.
scale ( expression )
The value of the scale function is the number of digits after the
decimal point in the expression.
sqrt ( expression )
The value of the sqrt function is the square root of the expres-
sion. If the expression is negative, a run time error is gener-
ated.
STATEMENTS
Statements (as in most algebraic languages) provide the sequencing of
expression evaluation. In bc statements are executed "as soon as possi-
ble." Execution happens when a newline in encountered and there is one
or more complete statements. Due to this immediate execution, newlines
are very important in bc. In fact, both a semicolon and a newline are
used as statement separators. An improperly placed newline will cause a
syntax error. Because newlines are statement separators, it is possible
to hide a newline by using the backslash character. The sequence
"\<nl>", where <nl> is the newline appears to bc as whitespace instead
of a newline. A statement list is a series of statements separated by
semicolons and newlines. The following is a list of bc statements and
what they do: (Things enclosed in brackets ([]) are optional parts of
the statement.)
expression
This statement does one of two things. If the expression starts
with "<variable> <assignment> ...", it is considered to be an as-
signment statement. If the expression is not an assignment
statement, the expression is evaluated and printed to the output.
After the number is printed, a newline is printed. For example,
"a=1" is an assignment statement and "(a=1)" is an expression
that has an embedded assignment. All numbers that are printed
are printed in the base specified by the variable obase. The le-
gal values for obase are 2 through BC_BASE_MAX. (See the section
LIMITS.) For bases 2 through 16, the usual method of writing
numbers is used. For bases greater than 16, bc uses a multi-
character digit method of printing the numbers where each higher
base digit is printed as a base 10 number. The multi-character
digits are separated by spaces. Each digit contains the number
of characters required to represent the base ten value of
"obase-1". Since numbers are of arbitrary precision, some num-
bers may not be printable on a single output line. These long
numbers will be split across lines using the "\" as the last
character on a line. The maximum number of characters printed
per line is 70. Due to the interactive nature of bc, printing a
number causes the side effect of assigning the printed value to
the special variable last. This allows the user to recover the
last value printed without having to retype the expression that
printed the number. Assigning to last is legal and will over-
write the last printed value with the assigned value. The newly
assigned value will remain until the next number is printed or
another value is assigned to last. (Some installations may allow
the use of a single period (.) which is not part of a number as a
short hand notation for for last.)
string The string is printed to the output. Strings start with a double
quote character and contain all characters until the next double
quote character. All characters are take literally, including
any newline. No newline character is printed after the string.
print list
The print statement (an extension) provides another method of
output. The "list" is a list of strings and expressions sepa-
rated by commas. Each string or expression is printed in the or-
der of the list. No terminating newline is printed. Expressions
are evaluated and their value is printed and assigned to the
variable last. Strings in the print statement are printed to the
output and may contain special characters. Special characters
start with the backslash character (\). The special characters
recognized by bc are "a" (alert or bell), "b" (backspace), "f"
(form feed), "n" (newline), "r" (carriage return), "q" (double
quote), "t" (tab), and "\" (backslash). Any other character fol-
lowing the backslash will be ignored.
{ statement_list }
This is the compound statement. It allows multiple statements to
be grouped together for execution.
if ( expression ) statement1 [else statement2]
The if statement evaluates the expression and executes statement1
or statement2 depending on the value of the expression. If the
expression is non-zero, statement1 is executed. If statement2 is
present and the value of the expression is 0, then statement2 is
executed. (The else clause is an extension.)
while ( expression ) statement
The while statement will execute the statement while the expres-
sion is non-zero. It evaluates the expression before each execu-
tion of the statement. Termination of the loop is caused by a
zero expression value or the execution of a break statement.
for ( [expression1] ; [expression2] ; [expression3] ) statement
The for statement controls repeated execution of the statement.
Expression1 is evaluated before the loop. Expression2 is evalu-
ated before each execution of the statement. If it is non-zero,
the statement is evaluated. If it is zero, the loop is termi-
nated. After each execution of the statement, expression3 is
evaluated before the reevaluation of expression2. If expression1
or expression3 are missing, nothing is evaluated at the point
they would be evaluated. If expression2 is missing, it is the
same as substituting the value 1 for expression2. (The optional
expressions are an extension. POSIX bc requires all three ex-
pressions.) The following is equivalent code for the for state-
ment:
expression1;
while (expression2) {
statement;
expression3;
}
break This statement causes a forced exit of the most recent enclosing
while statement or for statement.
continue
The continue statement (an extension) causes the most recent en-
closing for statement to start the next iteration.
halt The halt statement (an extension) is an executed statement that
causes the bc processor to quit only when it is executed. For
example, "if (0 == 1) halt" will not cause bc to terminate be-
cause the halt is not executed.
return Return the value 0 from a function. (See the section on func-
tions.)
return ( expression )
Return the value of the expression from a function. (See the
section on functions.) As an extension, the parenthesis are not
required.
PSEUDO STATEMENTS
These statements are not statements in the traditional sense. They are
not executed statements. Their function is performed at "compile" time.
limits Print the local limits enforced by the local version of bc. This
is an extension.
quit When the quit statement is read, the bc processor is terminated,
regardless of where the quit statement is found. For example,
"if (0 == 1) quit" will cause bc to terminate.
warranty
Print a longer warranty notice. This is an extension.
FUNCTIONS
Functions provide a method of defining a computation that can be exe-
cuted later. Functions in bc always compute a value and return it to
the caller. Function definitions are "dynamic" in the sense that a
function is undefined until a definition is encountered in the input.
That definition is then used until another definition function for the
same name is encountered. The new definition then replaces the older
definition. A function is defined as follows:
define name ( parameters ) { newline
auto_list statement_list }
A function call is just an expression of the form "name(parameters)".
Parameters are numbers or arrays (an extension). In the function defin-
ition, zero or more parameters are defined by listing their names sepa-
rated by commas. All parameters are call by value parameters. Arrays
are specified in the parameter definition by the notation "name[]". In
the function call, actual parameters are full expressions for number pa-
rameters. The same notation is used for passing arrays as for defining
array parameters. The named array is passed by value to the function.
Since function definitions are dynamic, parameter numbers and types are
checked when a function is called. Any mismatch in number or types of
parameters will cause a runtime error. A runtime error will also occur
for the call to an undefined function.
The auto_list is an optional list of variables that are for "local" use.
The syntax of the auto list (if present) is "auto name, ... ;". (The
semicolon is optional.) Each name is the name of an auto variable. Ar-
rays may be specified by using the same notation as used in parameters.
These variables have their values pushed onto a stack at the start of
the function. The variables are then initialized to zero and used
throughout the execution of the function. At function exit, these vari-
ables are popped so that the original value (at the time of the function
call) of these variables are restored. The parameters are really auto
variables that are initialized to a value provided in the function call.
Auto variables are different than traditional local variables because if
function A calls function B, B may access function A's auto variables by
just using the same name, unless function B has called them auto vari-
ables. Due to the fact that auto variables and parameters are pushed
onto a stack, bc supports recursive functions.
The function body is a list of bc statements. Again, statements are
separated by semicolons or newlines. Return statements cause the termi-
nation of a function and the return of a value. There are two versions
of the return statement. The first form, "return", returns the value 0
to the calling expression. The second form, "return ( expression )",
computes the value of the expression and returns that value to the call-
ing expression. There is an implied "return (0)" at the end of every
function. This allows a function to terminate and return 0 without an
explicit return statement.
Functions also change the usage of the variable ibase. All constants in
the function body will be converted using the value of ibase at the time
of the function call. Changes of ibase will be ignored during the exe-
cution of the function except for the standard function read, which will
always use the current value of ibase for conversion of numbers.
Several extensions have been added to functions. First, the format of
the definition has been slightly relaxed. The standard requires the
opening brace be on the same line as the define keyword and all other
parts must be on following lines. This version of bc will allow any
number of newlines before and after the opening brace of the function.
For example, the following definitions are legal.
define d (n) { return (2*n); }
define d (n)
{ return (2*n); }
Functions may be defined as void. A void function returns no value and
thus may not be used in any place that needs a value. A void function
does not produce any output when called by itself on an input line. The
key word void is placed between the key word define and the function
name. For example, consider the following session.
define py (y) { print "--->", y, "<---", "\n"; }
define void px (x) { print "--->", x, "<---", "\n"; }
py(1)
--->1<---
0
px(1)
--->1<---
Since py is not a void function, the call of py(1) prints the desired
output and then prints a second line that is the value of the function.
Since the value of a function that is not given an explicit return
statement is zero, the zero is printed. For px(1), no zero is printed
because the function is a void function.
Also, call by variable for arrays was added. To declare a call by vari-
able array, the declaration of the array parameter in the function defi-
nition looks like "*name[]". The call to the function remains the same
as call by value arrays.
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.
EXAMPLES
In /bin/sh, the following will assign the value of "pi" to the shell
variable pi.
pi=$(echo "scale=10; 4*a(1)" | bc -l)
The following is the definition of the exponential function used in the
math library. This function is written in POSIX bc.
scale = 20
/* Uses the fact that e^x = (e^(x/2))^2
When x is small enough, we use the series:
e^x = 1 + x + x^2/2! + x^3/3! + ...
*/
define e(x) {
auto a, d, e, f, i, m, v, z
/* Check the sign of x. */
if (x<0) {
m = 1
x = -x
}
/* Precondition x. */
z = scale;
scale = 4 + z + .44*x;
while (x > 1) {
f += 1;
x /= 2;
}
/* Initialize the variables. */
v = 1+x
a = x
d = 1
for (i=2; 1; i++) {
e = (a *= x) / (d *= i)
if (e == 0) {
if (f>0) while (f--) v = v*v;
scale = z
if (m) return (1/v);
return (v/1);
}
v += e
}
}
The following is code that uses the extended features of bc to implement
a simple program for calculating checkbook balances. This program is
best kept in a file so that it can be used many times without having to
retype it at every use.
scale=2
print "\nCheck book program!\n"
print " Remember, deposits are negative transactions.\n"
print " Exit by a 0 transaction.\n\n"
print "Initial balance? "; bal = read()
bal /= 1
print "\n"
while (1) {
"current balance = "; bal
"transaction? "; trans = read()
if (trans == 0) break;
bal -= trans
bal /= 1
}
quit
The following is the definition of the recursive factorial function.
define f (x) {
if (x <= 1) return (1);
return (f(x-1) * x);
}
READLINE AND LIBEDIT OPTIONS
GNU bc can be compiled (via a configure option) to use the GNU readline
input editor library or the BSD libedit library. This allows the user
to do editing of lines before sending them to bc. It also allows for a
history of previous lines typed. When this option is selected, bc has
one more special variable. This special variable, history is the number
of lines of history retained. For readline, a value of -1 means that an
unlimited number of history lines are retained. Setting the value of
history to a positive number restricts the number of history lines to
the number given. The value of 0 disables the history feature. The de-
fault value is 100. For more information, read the user manuals for the
GNU readline, history and BSD libedit libraries. One can not enable
both readline and libedit at the same time.
DIFFERENCES
This version of bc was implemented from the POSIX P1003.2/D11 draft and
contains several differences and extensions relative to the draft and
traditional implementations. It is not implemented in the traditional
way using dc(1). This version is a single process which parses and runs
a byte code translation of the program. There is an "undocumented" op-
tion (-c) that causes the program to output the byte code to the stan-
dard output instead of running it. It was mainly used for debugging the
parser and preparing the math library.
A major source of differences is extensions, where a feature is extended
to add more functionality and additions, where new features are added.
The following is the list of differences and extensions.
LANG environment
This version does not conform to the POSIX standard in the pro-
cessing of the LANG environment variable and all environment
variables starting with LC_.
names Traditional and POSIX bc have single letter names for functions,
variables and arrays. They have been extended to be multi-char-
acter names that start with a letter and may contain letters,
numbers and the underscore character.
Strings
Strings are not allowed to contain NUL characters. POSIX says
all characters must be included in strings.
last POSIX bc does not have a last variable. Some implementations of
bc use the period (.) in a similar way.
comparisons
POSIX bc allows comparisons only in the if statement, the while
statement, and the second expression of the for statement. Also,
only one relational operation is allowed in each of those state-
ments.
if statement, else clause
POSIX bc does not have an else clause.
for statement
POSIX bc requires all expressions to be present in the for state-
ment.
&&, ||, !
POSIX bc does not have the logical operators.
read function
POSIX bc does not have a read function.
print statement
POSIX bc does not have a print statement.
continue statement
POSIX bc does not have a continue statement.
return statement
POSIX bc requires parentheses around the return expression.
array parameters
POSIX bc does not (currently) support array parameters in full.
The POSIX grammar allows for arrays in function definitions, but
does not provide a method to specify an array as an actual para-
meter. (This is most likely an oversight in the grammar.) Tra-
ditional implementations of bc have only call by value array pa-
rameters.
function format
POSIX bc requires the opening brace on the same line as the de-
fine key word and the auto statement on the next line.
=+, =-, =*, =/, =%, =^
POSIX bc does not require these "old style" assignment operators
to be defined. This version may allow these "old style" assign-
ments. Use the limits statement to see if the installed version
supports them. If it does support the "old style" assignment op-
erators, the statement "a =- 1" will decrement a by 1 instead of
setting a to the value -1.
spaces in numbers
Other implementations of bc allow spaces in numbers. For exam-
ple, "x=1 3" would assign the value 13 to the variable x. The
same statement would cause a syntax error in this version of bc.
errors and execution
This implementation varies from other implementations in terms of
what code will be executed when syntax and other errors are found
in the program. If a syntax error is found in a function defini-
tion, error recovery tries to find the beginning of a statement
and continue to parse the function. Once a syntax error is found
in the function, the function will not be callable and becomes
undefined. Syntax errors in the interactive execution code will
invalidate the current execution block. The execution block is
terminated by an end of line that appears after a complete se-
quence of statements. For example,
a = 1
b = 2
has two execution blocks and
{ a = 1
b = 2 }
has one execution block. Any runtime error will terminate the execution
of the current execution block. A runtime warning will not terminate
the current execution block.
Interrupts
During an interactive session, the SIGINT signal (usually gener-
ated by the control-C character from the terminal) will cause ex-
ecution of the current execution block to be interrupted. It
will display a "runtime" error indicating which function was in-
terrupted. After all runtime structures have been cleaned up, a
message will be printed to notify the user that bc is ready for
more input. All previously defined functions remain defined and
the value of all non-auto variables are the value at the point of
interruption. All auto variables and function parameters are re-
moved during the clean up process. During a non-interactive ses-
sion, the SIGINT signal will terminate the entire run of bc.
LIMITS
The following are the limits currently in place for this bc processor.
Some of them may have been changed by an installation. Use the limits
statement to see the actual values.
BC_BASE_MAX
The maximum output base is currently set at 999. The maximum in-
put base is 16.
BC_DIM_MAX
This is currently an arbitrary limit of 65535 as distributed.
Your installation may be different.
BC_SCALE_MAX
The number of digits after the decimal point is limited to
INT_MAX digits. Also, the number of digits before the decimal
point is limited to INT_MAX digits.
BC_STRING_MAX
The limit on the number of characters in a string is INT_MAX
characters.
exponent
The value of the exponent in the raise operation (^) is limited
to LONG_MAX.
variable names
The current limit on the number of unique names is 32767 for each
of simple variables, arrays and functions.
ENVIRONMENT VARIABLES
The following environment variables are processed by bc:
POSIXLY_CORRECT
This is the same as the -s option.
BC_ENV_ARGS
This is another mechanism to get arguments to bc. The format is
the same as the command line arguments. These arguments are
processed first, so any files listed in the environment arguments
are processed before any command line argument files. This al-
lows the user to set up "standard" options and files to be
processed at every invocation of bc. The files in the environ-
ment variables would typically contain function definitions for
functions the user wants defined every time bc is run.
BC_LINE_LENGTH
This should be an integer specifying the number of characters in
an output line for numbers. This includes the backslash and new-
line characters for long numbers. As an extension, the value of
zero disables the multi-line feature. Any other value of this
variable that is less than 3 sets the line length to 70.
DIAGNOSTICS
If any file on the command line can not be opened, bc will report that
the file is unavailable and terminate. Also, there are compile and run
time diagnostics that should be self-explanatory.
BUGS
Error recovery is not very good yet.
Email bug reports to bug-bc@gnu.org. Be sure to include the word ``bc''
somewhere in the ``Subject:'' field.
AUTHOR
Philip A. Nelson
philnelson@acm.org
ACKNOWLEDGEMENTS
The author would like to thank Steve Sommars (Steve.Sommars@att.com) for
his extensive help in testing the implementation. Many great sugges-
tions were given. This is a much better product due to his involvement.
GNU Project 2006-06-11 bc(1)
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