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Full Discussion: Plotting A Sine Curve Inside A Bash Shell...
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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LEARN ABOUT LINUX

shtool-path

SHTOOL-PATH.TMP(1)					      GNU Portable Shell Tool						SHTOOL-PATH.TMP(1)

NAME

       shtool-path - GNU shtool command dealing with shell path variables

SYNOPSIS

       shtool path [-s|--suppress] [-r|--reverse] [-d|--dirname] [-b|--basename] [-m|--magic] [-p|--path path] str [str ...]

DESCRIPTION

       This command deals with shell $PATH variables. It can find a program through one or more filenames given by one or more str arguments.  It
       prints the absolute filesystem path to the program displayed on "stdout" plus an exit code of 0 if it was really found.

OPTIONS

       The following command line options are available.

       -s, --suppress
	   Supress output. Useful to only test whether a program exists with the help of the return code.

       -r, --reverse
	   Transform a forward path to a subdirectory into a reverse path.

       -d, --dirname
	   Output the directory name of str.

       -b, --basename
	   Output the base name of str.

       -m, --magic
	   Enable advanced magic search for ""perl"" and ""cpp"".

       -p, --path path
	   Search in path. Default is to search in $PATH.

EXAMPLE

	#   shell script
	awk=`shtool path -p "${PATH}:." gawk nawk awk`
	perl=`shtool path -m perl`
	cpp=`shtool path -m cpp`
	revpath=`shtool path -r path/to/subdir`

HISTORY

       The GNU shtool path command was originally written by Ralf S.  Engelschall <rse@engelschall.com> in 1998 for Apache. It was later taken
       over into GNU shtool.

SEE ALSO

       shtool(1), which(1).

18-Jul-2008							   shtool 2.0.8 						SHTOOL-PATH.TMP(1)
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