I have a file named Atoms that has a list of atoms listed vertically, like:

O
C
Na

etc. There is a variable number of them.

I want to count their occurences in another file. I want to do this by saving each atom as a variable, preferabbly in an associative array, then counting how many there are in the other file. I already can count the number of atoms, and I save that into $numatoms

My problem right now is the awk command recognizing the variable $i from the for loop. The part where it says NR=="$i" doesn't seem to work. Also, afterward, I still wouldn't know how to count the occurences in another file, which is also based on a variable, titled $name.axyz. I'm fairly new, and help would be appreciated!!! Thanks.


for (( i=1; i < $numatoms; i++ )); do
count[$i]=$(awk {'NR=='"$i"'{ print "$1"}' Atoms)
echo $count[$i]
done

Use only awk:

awk '{a[$0]++}END{for (i in a) printf "%s\t%s %s\n",i,a[i],"Atoms"}' file > new_file

Sorry, I'm really new to awk, could you explain your line a little? I tried it and it didn't work. What is meant by file and new_file for, is that where the searching is done? Thanks

awk '{
a[$0]++                               #read each line($0) from source file in array a and count ++ occurrences of $0
}
END                                   #at the end of file do..
{
for (i in a)                          #for each member (i)of array a
printf "%s\t%s %s\n",i,a[i],"Atoms"   #format the output, read man printf for more options
}
' file > new_file                     #declare the source file and set the output (>) to new_file