Okay, this probably sounds dumb for anyone who knows the answer, but I'm completely lost. I have to use the head command to search a directory AND all of its subdirectories to display the first line of all .txt files. I know how to do this: head -1 ~/UnixCourse/*.txt, but that does not search the... (4 Replies)
Hi All,
How can the head command be used to extract only a particular line.
By default head -n filename displays the first n lines. I want only the nth line.
I couldn't get it from forum search.
Thanks,
Sumesh (6 Replies)
Hi friends,I am new to unix and this is really a dummy question.but please help me out.
How to simulate head command without using head command???
also tail command too,also more command.
it is given as a homework to do....please tell me how to do (2 Replies)
Hi, I have the following problem. I have files with one column of data (let's say file1.dat, file2.dat...file6.dat), and I would like to record the first value of the column of each file into another file (let's name it fileall.dat), which would have the the six values, one in each column. I use to... (4 Replies)
Hi,
I have been given assignment of 30 scripts out of which I was able to solve many, I need help with few out of which one asks to imitate head and tail command of unix without using the head and tail commands. Problem is stated below:
Write an interactive shell script to imitate the head... (5 Replies)
Use and complete the template provided. The entire template must be completed. If you don't, your post may be deleted!
1. The problem statement, all variables and given/known data:
I've been stuck on this problem for 2 days now
What command would you enter to list the first lines of all text... (11 Replies)
Hi,
I need some advise on whether there is a better way of doing what I am currently planning to do. Perhaps I should be using arrays instead of re-directing output to files?
I need to use a tool/program named ADRCI provided by Oracle to remove trace files that it generates. Honestly it is... (1 Reply)
Use and complete the template provided. The entire template must be completed. If you don't, your post may be deleted!
1. The problem statement, all variables and given/known data:
Write a script that allows the user to print the first n lines or the last n lines of every file in the... (18 Replies)
Discussion started by: lukefrost96
18 Replies
LEARN ABOUT DEBIAN
numm.spectral-analysis
spectral-analysis(7) Numm Tutorials spectral-analysis(7)NAME
spectral analysis - perform realtime spectral analysis
SYNOPSIS
numm-run FILE
DESCRIPTION
Frequency makes for a meaningful description of many audio signals. We can use numpy's fourier analysis to compute spectra from the micro-
phone and display the results visually. We will break down the process into smaller parts: baby steps...
First, create and save a skeletal file that moves a line across the screen:
idx = 0
def video_out(a):
global idx
a[:,idx] = 255
idx = (idx + 1) % a.shape[1]
def audio_in(a):
pass
Save this snippet and run it with numm-run.
We will use the numpy.fft module for our analysis. First we define a function to get a particular frequency from the fourier transform:
import numpy as np
def get_freq(fourier, frequency):
freqs = np.fft.fftfreq(len(fourier), 1/44100.0)
nearest = (abs(freqs - frequency)).argmin()
return abs(fourier[nearest])
Next, we hook up this function to audio input from the microphone. A frequency bin is chosen on a log scale for each row on the screen to
display a spectogram. In total:
import numpy as np
idx = 0
recent_audio = np.zeros(4096, np.int16)
recent_video = np.zeros((240,320,3), np.uint8)
freq_bins = np.exp2(np.linspace(np.log2(27000),np.log2(27),240))
def get_freq(fourier, frequency):
freqs = np.fft.fftfreq(len(fourier), 1/44100.0)
nearest = (abs(freqs - frequency)).argmin()
return abs(fourier[nearest])
def video_out(a):
global idx
fourier=np.fft.fft(recent_audio)
values =np.array([get_freq(fourier,X) for X in freq_bins])
recent_video[:,idx,1] = (values/10000).clip(0,255)
idx = (idx + 1) % a.shape[1]
a[:] = np.roll(recent_video, -idx, axis=1)
def audio_in(a):
recent_audio[:] = np.roll(recent_audio, len(a))
recent_audio[:len(a)] = a.mean(axis=1)
SEE ALSO numm-run(1), numm.getting-started(7), numm.one-bit-instrument(7)numm February 2012 spectral-analysis(7)