rcalc - record calculator |

rcalc [ -b ][ -l ][ -n ][
-w ][ -u ][ -tS ][ -i format ][
-o format ][ -f source ][ -e expr ][
-s svar=sval ] file .. |

Rcalc transforms ``records'' from each file
according to the given set of literal and relational
information. By default, records are separated by newlines,
and contain numeric fields separated by tabs. The -tS
option is used to specify an alternate tab character. A
-i format option specifies a template for an
alternate input record format. Format is interpreted
as a specification string if it contains a dollar sign '$'.
Otherwise, it is interpreted as the name of the file
containing the format specification. In either case, if the
format does not end with a newline, one will be added
automatically. A -o format option specifies an
alternate output record format. It is interpreted the same
as an input specification. The variable and function
definitions in each -f source file are read and
compiled. The -e expr option can be used to define
variables on the command line. Since many of the characters
in an expression have special meaning to the shell, it
should usually be enclosed in single quotes. The -s
svar=sval option can be used to assign a string variable
a string value. If this string variable appears in an input
format, only records with the specified value will be
processed. The -b option instructs the program to
accept only exact matches. By default, tabs and spaces are
ignored except as field separators. The -l option
instructs the program to ignore newlines in the input,
basically treating them the same as tabs and spaces.
Normally, the beginning of the input format matches the
beginning of a line, and the end of the format matches the
end of a line. With the -l option, the input format
can match anywhere on a line. The -w option causes
non-fatal error messages (such as division by zero) to be
supressed. The -u option causes output to be flushed
after each record. The -n option tells the program
not to get any input, but to produce a single output record.
Otherwise, if no files are given, the standard input is
read. |

Format files associate names with string and numeric fields separated by literal information in a record. A numeric field is given in a format file as a dollar sign, followed by curly braces enclosing a variable name: |

This is a numeric field: ${vname} |

A string variable is enclosed in parentheses: |

This is a string field: $(sname) |

The program attempts to match literal information in the input format to its input and assign string and numeric fields accordingly. If a string or numeric field variable appears more than once in the input format, input values for the corresponding fields must match (ie. have the same value) for the whole record to match. Numeric values are allowed some deviation, on the order of 0.1%, but string variables must match exactly. Thus, dummy variables for "don't care" fields should be given unique names so that they are not all required to take on the same value. |

For each valid input record, an output record is produced in
its corresponding format. Output field widths are given
implicitly by the space occupied in the format file,
including the dollar sign and braces. This makes it
impossible to produce fields with fewer than four
characters. If the -b option is specified, input
records must exactly match the template. By default, the
character following each input field is used as a delimiter.
This implies that string fields that are followed by white
space cannot contain strings with white space. Also, numeric
fields followed but not preceded by white space will not
accept numbers preceded by white space. Adjacent input
fields are advisable only with the -b option. Numeric
output fields may contain expressions as well as variables.
A dollar sign may appear in a literal as two dollar signs
($$). |

The definitions specified in -e and -f options
relate numeric output fields to numeric input fields. For
the default record format, a field is a variable of the form
$N, where N is the column number, beginning with 1. Output
columns appear on the left-hand side of assignments, input
columns appear on the right-hand side. |

A variable definition has the form: |

var = expression ; |

Any instance of the variable in an expression will be replaced with its definition. |

An expression contains real numbers, variable names, function calls, and the following operators: |

+ - * / ^ |

Operators are evaluated left to right. Powers have the highest precedence; multiplication and division are evaluated before addition and subtraction. Expressions can be grouped with parentheses. All values are double precision real. |

A function definition has the form: |

func(a1, a2, ..) = expression ; |

The expression can contain instances of the function arguments as well as other variables and functions. Function names can be passed as arguments. Recursive functions can be defined using calls to the defined function or other functions calling the defined function. |

The variable cond, if defined, will determine whether
the current input record produces an output record. If
cond is positive, output is produced. If cond
is less than or equal to zero, the record is skipped and no
other expressions are evaluated. This provides a convenient
method for avoiding inappropriate calculations. The
following library of pre-defined functions and variables is
provided: |

if(cond, then, else) |

if cond is greater than zero, then is evaluated, otherwise else is evaluated. This function is necessary for recursive definitions. |

select(N, a1, a2, ..) |

return aN (N is rounded to the nearest integer). This
function provides array capabilities. If N is zero,
the number of available arguments is returned. |

rand(x) |

compute a random number between 0 and 1 based on x. |

floor(x) |

return largest integer not greater than x. |

ceil(x) |

return smallest integer not less than x. |

sqrt(x) |

return square root of x. |

exp(x) |

compute e to the power of x (e approx = 2.718281828). |

log(x) |

compute the logarithm of x to the base e. |

log10(x) |

compute the logarithm of x to the base 10. |

PI the ratio of a circle's circumference to its
diameter. |

recno |

the number of records recognized thus far. |

sin(x), cos(x), tan(x) |

trigonometric functions. |

asin(x), acos(x), atan(x) |

inverse trigonometric functions. |

atan2(y, x) |

inverse tangent of y/x (range -pi to pi). |

To print the square root of column two in column one, and column one times column three in column two: |

rcalc -e '$1=sqrt($2);$2=$1*$3' inputfile > outputfile |

Greg Ward |

String variables can only be used in input and output
formats and -s options, not in
definitions. |

Tabs count as single spaces inside fields. |

calc(1), cnt(1), ev(1), lam(1), tabfunc(1), total(1) |

http://www.schorsch.com/en/software/rayfront/manual/htmlman/rcalc.html

Copyright © 2004-2013 schorsch.com

Copyright © 2004-2013 schorsch.com