UNIX for Dummies Questions & Answers

Hi guys
New to scripting, I have many data files and I'm having real trouble with a script for the following:

For all files that end in *.dat
i want to get the mean of column6 ($6/NR)

and send each mean to column2 in a new file where column1 would represent the name of the original files
e.g. 090112 4.32
090111 5.67
090110 3.70

thirdly I'd like to add a third column to this file which is:
$3 = 2 * exp(3 * $2 -1)

I'd really appreciate any help as I've been banging my head against the wall.

Larry

One way:

Code:

awk '
NR==1{f=FILENAME;s=$6;next}
FILENAME != f {
  printf("%s %d %d\n", substr(f,1,match(f,".")), s/n, 2*exp(3*(s/n)-1))
  f=FILENAME
  s=0
} 
{s+=$6;n=FNR}
END{
  printf("%s %d %d\n", substr(f,1,match(f,".")), s/n, 2*exp(3*(s/n)-1))
}' *.dat

Regards

Thanks very much Franklin52, running that script initially yields something like this (see below) so there must be a few things I'll need to change but it's certainly pointed me in the right direction.

0 0/n0 1 0/n0 1 0/n0 1 0/n0 0 0/n0 0 0/n0 1 0/n0 0 0/n0 1 0/n0 1 0/n0 0 0/n0 1 0/n0 1 0/n0 1 1/n0 0 0/n0 1 0/n0 1 1/n0 1 1/n0 1 1/n0 1 1/n0 1 1/n0 1 1/n0 1 0/n0 1 1/n0 1 1/n0 1 1/n0 1 1/n0 1 1/n0 1 1/n0 1 0/n0 1 1/n0 1 1/n0 1 1/n0 1 1/n0 1 1/n0 1 1/n0 1 1/n0 1 2/n0 1 1/n0 1 1/n0 1 2/n0 1 2/n0 1 1/n0 1 2/n0 1 1/n0 1 2/n0 1 1/n0 1 1/n0 1 3/n0 1 1/

Regards Larry

I assume the format of the .dat files are identical, right? Can you post a snippet of the output of one of the dat files?

Regards

The format is identical though I just realised the data is separated by commas:

1018.62, 270.53, 4.76, 75.70, 8.72, 2.122, 0, 16:07:53, 2008/12/17, 0.006
1018.87, 271.95, 4.30, 75.82, 8.72, 1.984, 0, 16:12:53, 2008/12/17, 0.001
1018.87, 275.13, 4.47, 75.82, 9.08, 1.874, 0, 16:17:53, 2008/12/17, 0.002
1018.62, 281.05, 5.92, 76.19, 8.96, 1.752, 0, 16:22:53, 2008/12/17, 0.000
1018.87, 277.98, 4.62, 77.17, 8.72, 1.563, 0, 16:27:53, 2008/12/17, 0.002

Change the fieldseparator:

Code:

awk -F, '
NR==1{f=FILENAME;s=$6;next}
FILENAME != f {
  printf("%s %d %d\n", substr(f,1,match(f,".")), s/n, 2*exp(3*(s/n)-1))
  f=FILENAME
  s=0
} 
{s+=$6;n=FNR}
END{
  printf("%s %d %d\n", substr(f,1,match(f,".")), s/n, 2*exp(3*(s/n)-1))
}' *.dat

Regards