04-16-2018
Consider the difference between || and &&
This User Gave Thanks to Scrutinizer For This Post:
7 More Discussions You Might Find Interesting
1. UNIX for Dummies Questions & Answers
Hello guys..
well, im kinda newbie with unix because i started to learn it like 2 weeks ago.
then i started to make some exercises, but i got stucked on this one :
so, i need to know how many different 'names' has the 5th field and how many times each name appears.
i was trying with a... (6 Replies)
Discussion started by: EnioMarques
6 Replies
2. UNIX for Dummies Questions & Answers
Hello guys.
Well, on this exercise i need the average "chargeAmount" per hour (for each hour).
with this code :
cat getusagesummarywrongmatch | grep -iv MOU2GRTObject | cut -d'|' -f4,14 | grep -i chargeamount | cut -d' ' -f2
http://img227.imageshack.us/img227/5889/65969235do0.jpg
i got... (2 Replies)
Discussion started by: EnioMarques
2 Replies
3. Shell Programming and Scripting
How do I write a shell script file to read 5 student names (First and Last name) and their grades using a While Loop? Find the Average, Maximum, and Minimum of grades using the same While Loop. Prompt the user using tput to enter the information (first name, last name, grade). Save the data in a... (1 Reply)
Discussion started by: dlbomber1
1 Replies
4. Shell Programming and Scripting
Hi, 'm trying to do an exercicise, and one part is:
ls -l $1 | awk '
BEGIN {
max = $5;
}
{
if ($5 > max){
max = $5;
}
}
END {
print "Tamanio mayor fichero = " max; }'
# Imprimimos ahora el menor tamaņo de fichero
ls -l $1 | awk '... (4 Replies)
Discussion started by: Phass
4 Replies
5. Homework & Coursework Questions
you are to write a program which will read in a tax rate (as a percentage) and the prices of 5 items. the program is to calculate the total price, before tax, of the items and then the tax payable on those items, and then the total amount due. the tax payable is computed by appliying the tax rate... (1 Reply)
Discussion started by: bunkercrazy
1 Replies
6. Shell Programming and Scripting
hello everyone!:)
I have an exercise which I think is difficult for beginner like me. Here is the exercise
Create a shell script, which takes a directory as command line argument.
Script displays ten first lines from every text file in that directory. After
displaying the lines from the... (1 Reply)
Discussion started by: googlevn
1 Replies
7. UNIX for Dummies Questions & Answers
Hi,
I am learning unix. I want to practice few small excercises. Please suggest me some goor URL to practice.
Thanks in advance. (1 Reply)
Discussion started by: stew
1 Replies
LEARN ABOUT DEBIAN
pnmpsnr
pnmpsnr(1) General Commands Manual pnmpsnr(1)
NAME
pnmpsnr - compute the difference between two portable anymaps
SYNOPSIS
pnmpsnr [pnmfile1] [pnmfile2]
DESCRIPTION
Reads two PBM, PGM, or PPM files, or PAM equivalents, as input. Prints the peak signal-to-noise ratio (PSNR) difference between the two
images. This metric is typically used in image compression papers to rate the distortion between original and decoded image.
If the inputs are PBM or PGM, pnmpsnr prints the PSNR of the luminance only. Otherwise, it prints the separate PSNRs of the luminance, and
chrominance (Cb and Cr) components of the colors.
The PSNR of a given component is the ratio of the mean square difference of the component for the two images to the maximum mean square
difference that can exist betwee any two images. It is expressed as a decibel value.
The mean square difference of a component for two images is the mean square difference of the component value, comparing each pixel with
the pixel in the same position of the other image. For the purposes of this computation, components are normalized to the scale [0..1].
The maximum mean square difference is identically 1.
So the higher the PSNR, the closer the images are. A luminance PSNR of 20 means the mean square difference of the luminances of the pixels
is 100 times less than the maximum possible difference, i.e. 0.01.
SEE ALSO
pnm(5)
04 March 2001 pnmpsnr(1)