Shell Programming and Scripting

Hi,

I want to calculate std dev for a list of files and then print the output appended to an existing file.

I have a few folders within the directory Folder, and I am interested in getting the std dev of values in files named as time.txt. In the last pipe, if I print just the sd value, it works okay, but if I print $0 of the file time_a.txt, the sd value is zero, can someone tell me why.

Code:

cat Folder/num*/time.txt | awk '{print $6}' | awk '{x[NR]=$0; s+=$0} END{a=s/NR; 
   for (i in x){ss += (x[i]-a)^2} sd = sqrt(ss/NR); print sd,$0}' Folder/num1/time_a.txt

num1/time.txt

Code:

a b c d e 12
a b c d e 10

num2/time.txt

Code:

a b c d e 14
a b c d e 10

num1/time_a.txt

Code:

a b c d e 22

Expected output

Code:

a b c d e 22 std_dev

You cannot both read from stdin and a file in awk. You can use a - placeholder so that awk sees stdin as if it were a file..

Try for example:

Code:

echo hello | awk '{print}' file

vs.

Code:

echo hello | awk '{print}' - file