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1. Shell Programming and Scripting
In the below awk if I use the attached file as the input, I get no results for TCF4. However, if I just copy that line from the attached file and use that as input I get results for TCF4.
Basically the gene file is a 1 column list that is used to filter $8 of the attached file. When there is a... (9 Replies)
Discussion started by: cmccabe
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2. UNIX for Advanced & Expert Users
Hello
I have a data set which looks like this :
progeny sire dam gender
12 1 3 M
13 2 4 F
14 2 5 F
15 6 5 ... (13 Replies)
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3. Shell Programming and Scripting
Need to use dd to generate a large file from a sample file of random data. This is because I don't have /dev/urandom.
I create a named pipe then:
dd if=mynamed.fifo do=myfile.fifo bs=1024 count=1024
but when I cat a file to the fifo that's 1024 random bytes:
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4. Shell Programming and Scripting
Hello Unix experts,
I need a help to create a subset file. I know with cut comand, its very easy to select many different columns, or threshold. But here I have a bit problem as in my data file is big. And I don't want to identify the column numbers or names manually. I am trying to find any... (7 Replies)
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5. UNIX for Dummies Questions & Answers
Hi,
I'd like to swap the columns 1 and 2 of a space-delimited text file but only for the first 1000 rows. How do I go about doing that? Thanks! (1 Reply)
Discussion started by: evelibertine
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6. UNIX for Dummies Questions & Answers
Dear all,
I have a file lik below: n of row=420, n of letters in each row=100000 like below: there is no space between the letters.
what I want is: the 75000th letter to the 85000th letter in each row.
how to do that? thanks a lot!
... (2 Replies)
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7. Shell Programming and Scripting
OK, I am stumpped. I have this shell Script that I want to randomly select a file with the extention of .sct. Then using a portion of its file name select the six related .mot files. Then move them all to another folder. I also need a user input form for the number of .SCT files to randomly select... (6 Replies)
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8. Shell Programming and Scripting
Hi All,
I have some 6000 text files in a directory. My files are named like 1.txt, 2.txt 3.txt and so on until 6000.txt. I want to count the "number of words" in only first 3000 of them. Any suggestions?
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Discussion started by: shoaibjameel123
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9. Shell Programming and Scripting
>cat data.dat
0001 Robbert
0002 Nick
0003 Mark
.......
1000 Jarek (3 Replies)
Discussion started by: McLan
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10. UNIX for Dummies Questions & Answers
Hello!
I'm trying to find out the total file size of a subset list in a directory. For example, I do not need to know the total file size of all the files in a directory, but I need to know what the total size is of say, "ls -l *FEB08*" in a directory. Is there any easy way of doing this?
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RAND(3) Linux Programmer's Manual RAND(3)
NAME
rand, srand - random number generator.
SYNOPSIS
#include <stdlib.h>
int rand(void);
void srand(unsigned int seed);
DESCRIPTION
The rand() function returns a pseudo-random integer between 0 and RAND_MAX.
The srand() function sets its argument as the seed for a new sequence of pseudo-random integers to be returned by rand(). These sequences
are repeatable by calling srand() with the same seed value.
If no seed value is provided, the rand() function is automatically seeded with a value of 1.
RETURN VALUE
The rand() function returns a value between 0 and RAND_MAX. The srand() returns no value.
NOTES
The versions of rand() and srand() in the Linux C Library use the same random number generator as random() and srandom(), so the lower-
order bits should be as random as the higher-order bits. However, on older rand() implementations, the lower-order bits are much less ran-
dom than the higher-order bits.
In Numerical Recipes in C: The Art of Scientific Computing (William H. Press, Brian P. Flannery, Saul A. Teukolsky, William T. Vetterling;
New York: Cambridge University Press, 1992 (2nd ed., p. 277)), the following comments are made:
"If you want to generate a random integer between 1 and 10, you should always do it by using high-order bits, as in
j=1+(int) (10.0*rand()/(RAND_MAX+1.0));
and never by anything resembling
j=1+(rand() % 10);
(which uses lower-order bits)."
Random-number generation is a complex topic. The Numerical Recipes in C book (see reference above) provides an excellent discussion of
practical random-number generation issues in Chapter 7 (Random Numbers).
For a more theoretical discussion which also covers many practical issues in depth, please see Chapter 3 (Random Numbers) in Donald E.
Knuth's The Art of Computer Programming, volume 2 (Seminumerical Algorithms), 2nd ed.; Reading, Massachusetts: Addison-Wesley Publishing
Company, 1981.
CONFORMING TO
SVID 3, BSD 4.3, ISO 9899
SEE ALSO
random(3), srandom(3), initstate(3), setstate(3)
GNU
1995-05-18 RAND(3)