Shell Programming and Scripting

HI,

I have a file which i catenate and using the fields in the file, I would like to get sqrt of it. I tried to man the function but it normally would need an echo as well as bc.

What I am intending to find out is catenate a file where let say
cat a.txt| awk ' {
t= h*($3+$2);
t= 'sqrt($t)' | bc -l
count($1)=$2/t
}
END{

printf("the sqrt of %d is %d\n", $2,$1);
}
However, it does not work. Please help.


Thanks.


Rgrds,
Jason

Why?
Why cannot you use awk's 'sqrt'?

Hi ,

Do you mean using the same code that I described earlier on?


Please advise. Thanks.


-Jason

No, this 'code' will not work for multiple reasons.
What I mean (for starters) why cannot use awk's "sqrt" built-in function?
I guess I don't understand:

Hi,

The answer to this question is:-

1. what "t=sqrt($t)' | bc -l " is supposed to do
2. what is the value of 'h' in "t= h*($3+$2);"
I am basically trying to get an operation of two fields of columns $3 and $2 with multiplication of some constant value(h). These operation will end up giving me a number which is t. Then, this t value I would like to get its square root and assign to a new variable.

Perhaps I should write as "w=sqrt($t)" |bc -l in the first place.

3. What do think the value of $2 and $1 will be in the 'END' block
4. what's the intent of this: count($1)=$2/t
I would like to divide again the field of column 2 with the square root value to associate with field $1. Basically in my case, $1 is unique line number and $2 is just a numeric value for each line in the file a.txt.

5. why are you doing this 'cat a.txt'
The cat a.txt is bascially I would like to open the file which contains all the numbers and have 3 fields; $1, $2 and $3.

-Jason

Where the 'constant' (h) gets assigned it's value?
What do you think the value of '$t' in 'sqrt($t)' is?
Why are you trying "pipe" 'sqrt($t)' into 'bc -l'? Wouldn't a simple 't=sqrt(t)' be enough?
'count($1)' looks like a function 'count' taking a parameter with value of '$1'. And you're assigning '$2/t' to the function. This does not make any sense.
DO mean you want to use the associative array indexed by the value of your FIRST '$1' column? Something like that:

Code:

countArray[$1] = $2/t

The general awk paradigm for 'reading' files is:

Code:

awk '... awk BODY...' myInputFile.

Hi

Where the 'constant' (h) gets assigned it's value?
The h is actually counting the number of folders from other variables.

What do you think the value of '$t' in 'sqrt($t)' is?
Why are you trying "pipe" 'sqrt($t)' into 'bc -l'? Wouldn't a simple 't=sqrt(t)' be enough?
Yeah. I already tried on sqrt(t); which is without bc -l.


You are right. I am using associative array count for the purpose to read each line.

However, when I get the result from the operation, it doesnt return me the correct output from these operation.Did I missed out any "$" in the below fragment of code? It gives me INF and NAN value

cat a.txt| awk ' {
t= h*($3+$2);
s= sqrt($t)

count($1)=$2/s
}
END{

printf("the sqrt of %d is %d\n", $2,$1);
}

Please advise.Thanks.


Rgrds,
Jason