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up vote 2 down vote favorite

First of all: I hope the question is comprehensible, otherwise please let me know and I will do my best to make it more clear.

This is a follow up to Replace one entire column in one file with a single value from another file combined with R Pass Variable from R to Unix

Here goes:

I am running several scripts (Perl, python and R) in one Unix script and need to pass outputs of these scripts to Unix and combine information from different files these scripts create.

I have a working code which is a combination of the above mentioned questions:

The output from the R script called getenergie.R is a filename. There are several such filenames which are returned and I need to write into each of these files and replace column 11 of these files with a value which comes from another file (COP1A_report1) and is called value. 

RES=($(./../getenergies.R))
for pdbnames in "${RES[@]}"
do

#write the one value from COP1A_report1 into column 11 of a file and save as TESTING

value=$(awk -F, 'NR==1{print $2;exit}' ./../COP1A_report1) 
awk '{$11 = v} 1' v="$value" ${pdbnames} > TESTING

printf "$value ${pdbnames}\n"
done

What I need is a way to loop over this so that it writes one value from COP1A_report1 (row $2, line 1) into column 11 of a file called like the first filename stored in $pdbnames, save it as a unique file and go to COP1A_report1 (row $2, line 2), write that into column 11 of a file called like the second filename stored in $pdbnames and so on...

What is the smartest way of doing that? I can imagine sth like the code below, but sth is wrong with the syntax and I do not get any errors, just an empty value variable.

Any ideas?

counter=1
RES=($(./../getenergies.R))
for pdbnames in "${RES[@]}"
do

value=$(awk -F, 'NR==$counter{print $2;exit}' ./../COP1A_report1) #NR=1 needs to be changed to go through the entire list...
awk '{$11 = v} 1' v="$value" ${pdbnames} > TESTING$counter
counter=$(echo $counter+1 |bc)
printf "$value ${pdbnames}\n"
done
share|improve this question

1 Answer 1

up vote 0 down vote accepted

You're trying to pass $counter into the awk script, so you need to use double-quotes rather than single-quotes. Single-quotes are for literal strings, double-quotes are for strings with variables in them.

Because you're using double-quotes here, that means you have to escape $2 as \$2 in the awk script so that the shell doesn't substitute it's second arg (if any, empty string otherwise) into the awk script.

value=$(awk -F, "NR==$counter{print \$2;exit}" ./../COP1A_report1

You should also quote other variables when you use them. e.g. awk ... > "TESTING$counter" - lack of quotes was harmless in this instance, but always quoting your variables is a good habit to get into.

Same for counter=$(echo "$counter"+1 |bc) - not quoting is harmless here, but still bad practice.

Finally, you're missing the -v from the awk command when you set v="$value". should be -v v="$value"

counter=1
RES=($(./../getenergies.R))
for pdbnames in "${RES[@]}"
do

    value=$(awk -F, "NR==$counter{print \$2;exit}" ./../COP1A_report1)
    awk -v v="$value" '{$11 = v} 1' "$pdbnames" > "TESTING$counter"
    counter=$(echo "$counter"+1 |bc)
    printf "$value $pdbnames\n"

done
share|improve this answer
    
Ok. this works. I realise this is a bit off topic, but can you recommend a good blog/book etc on more good practices in unix programming? I would like to avoid the "don't s" in the future, wherever possible... – gugy Oct 28 at 8:50
    
can't recommend a book, but there's lots of good examples here. Look especially for answers by Stéphane Chazelas and Gilles....they really know their stuff and generally provide exceptionally well written and detailed answers. unix.stackexchange.com/users/22565/st%C3%A9phane-chazelas and unix.stackexchange.com/users/885/gilles – cas Oct 28 at 8:53

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