UNIX for Dummies Questions & Answers

Hi All,

I have four different files in four different directories.
Each file contains exactly the same format
logincode Forename Surname TutGroup Mark

Basically i want to grab all the marks from each file and put them onto the end of one login code by using a shell script. I can grab all the marks just by
cut -f 5 -d ' ' file1 file2 file3 file3

But then i want to add it on the end of the correct login code so i would have
logincode mark1 mark2 mark3 mark4

I have tried using join but can only do this for 2 files (i have 4) and it doesn't work if there is more than one record? i have tried
join -v 2 file1 file2 but this only displays record two.


Hope that makes sense
Regards
Jason

Code:

 awk '{c[$1]=c[$1]" "$5 }END{for (i in c){print i,c[i]}}' file1 file2 file3 file4

Your an absolute genius! It works perfectly!!!!
I don't really understand it all fully though. Could you explain?
Also if you wanted to do it without loops how could this be done?
I know how to use awk to calculate an average number for the whole file but how could i do this for one line? For example
50 60 70 (average mark here)
40 30 20 (average mark here)
Thanks

it creates an array for each firstfied, and adds on every 5th field where the firstfield atches... (the " " is the concatenation operator)

hmm - maybe not the clearest...hope the following makes more sense:

create array of values based on first col with concat 5th col values:

Code:

{c[$1]=c[$1]" "$5 }

Then loop through array and print out values:

Code:

{for (i in c){print i,c[i]}}'

for the average you could do:

Code:

 awk '{c[$1]=c[$1]" "$5 }END{for (i in c){print i,c[i]}}' file1 file2 file3 file4 | awk '{t=0;for (i = 2; i<=NF; i++) t+=$i;print $0,t/(NF - 1)}'

(i.e loop over 2nd through end cols, add 'em up and spit out the orig file with the avg tagged on...)