USAGE: floatexpr [<format>] <function> [<function>|<value> ..] <value>
  evaluates expressions and writes result to stdout.
  <value> is either a floating point number OR the name of a textfile,
  containing a floating point number, optionally preceded by
  a string of letters and/or underscore(s).
  If this is not the last <value> but the file does not exist
  and a default value is defined, that value is used instead.
  After "-prefix" and "-suffix" <value> is interpreted as a literal string.
FUNCTION:
 -add    sum of <value>s. Default: 0.
 -count  number of <value>s. Must be first and only function.
 -cosr   cos() of <result> in radians.
 -cosd   cos() of <result> in degrees.
 -cosg   cos() of <result> in grads.
 -diff   sum of all but last <value>s, minus last <value>. Default: 0.
 -div    divide <value> by last <value>. Default: 1.
 -exp    <result>=exp(<result>). Default: 1.
 -exp2   <result>=2^<result>. Default: 1.
 -exp10  <result>=10^<result>. Default: 1.
 -harm   write <first> <factor> <last> series. Must be first and only function.
 -int    result rounded off to nearest integer value.
 -ln     <result>=ln(<result>). Default: 0.
 -log10  <result>=10log(<result>). Default: 0.
 -log2   <result>=2log(<result>). Default: 0.
 -mean   mean value of <value>s. Default: 0.
 -mul    product of <value>s. Default: 1.
 -muldiv product of all but last <value>s, divided by last <value>. Default: 1.
 -prefix insert <value><space> before result.
 -rms    root mean square of <value>s. Default: 0.
 -series write <first> <step> <last> series. Must be first and only function.
 -sinr   sin() of <result> in radians.
 -sind   sin() of <result> in degrees.
 -sing   sin() of <result> in grads.
 -sqrt   square root of absolute value of result.
 -sub    sum of all but last <value>s, minus last <value>. Default: 0.
 -suffix append <space><value> after result.
 -sum    sum of <value>s. Default: 0.
 -sumdiv sum of all but last <value>s, divided by last <value>. Default: 1.
 -tanr   tan() of <result> in radians.
 -tand   tan() of <result> in degrees.
 -tang   tan() of <result> in grads.
NOTES: the last <value> can also be the result of a <function>.
       -prefix and -suffix should not be the last function.
FORMAT:
 -<n>d write result with <n> digit mantissa, no mantissa for integer values.
 -<n>f always write result with <n> digit mantissa.
 -<n>z write rounded off result preceded by zeros in <n> symbols.
 -<w>.<n> always write result in <w> symbols with <n> digit mantissa.
Default: -12d .
    On inability to read a number or open a file no output is written to stdout.
    Error messages are written to stderr.

Copyright (C) 2011 by Harm J. Schoonhoven

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
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VERSION: Jun 24 2014