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Operating Systems OS X (Apple) Plotting A Sine Curve Inside A Bash Shell... Post 302914577 by Corona688 on Tuesday 26th of August 2014 06:14:48 PM
Old 08-26-2014
I was trying to output direct 8-bit binary in awk. It kept converting my ff's into two-byte sequences.

You can, in GNU awk, with -b, which I was missing before:

Code:
$ # F is frequency, R is samplerate, S is number of samples
$ awk -b -v F=4000 -v R=8000 -v S=20 'BEGIN { for(N=0; N<S; N++) printf("%c", int(255*(sin(3.14159/2+2*3.14159*N*(F/R))/2)+128)) }' /dev/null | hexdump -C

00000000  ff 00 ff 00 ff 00 ff 00  ff 00 ff 00 ff 00 ff 00  |................|
00000010  ff 00 ff 00                                       |....|
00000014

$

Ordinary awk should be able to manage 1-127 with %c, but no more.

Last edited by Corona688; 08-26-2014 at 07:22 PM..
 

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English(3pm)						 Perl Programmers Reference Guide					      English(3pm)

NAME
English - use nice English (or awk) names for ugly punctuation variables SYNOPSIS
use English; use English qw( -no_match_vars ) ; # Avoids regex performance penalty # in perl 5.16 and earlier ... if ($ERRNO =~ /denied/) { ... } DESCRIPTION
This module provides aliases for the built-in variables whose names no one seems to like to read. Variables with side-effects which get triggered just by accessing them (like $0) will still be affected. For those variables that have an awk version, both long and short English alternatives are provided. For example, the $/ variable can be referred to either $RS or $INPUT_RECORD_SEPARATOR if you are using the English module. See perlvar for a complete list of these. PERFORMANCE
NOTE: This was fixed in perl 5.20. Mentioning these three variables no longer makes a speed difference. This section still applies if your code is to run on perl 5.18 or earlier. This module can provoke sizeable inefficiencies for regular expressions, due to unfortunate implementation details. If performance matters in your application and you don't need $PREMATCH, $MATCH, or $POSTMATCH, try doing use English qw( -no_match_vars ) ; . It is especially important to do this in modules to avoid penalizing all applications which use them. perl v5.18.2 2014-01-06 English(3pm)
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