BASH: Iterate range of numbers in a for cicle

Question

I want to create an array from a list of words. so, i'm using this code:

for i in {1..$count} 
do
array[$i]=$(cat file.txt | cut -d',' -f3 | sort -r | uniq | tail -n ${i})
done

but it fails... in tail -n ${i}

I already tried tail -n $i, tail -n $(i) but can't pass tail the value of i

Any ideas?

Answer 1

It fails because you cannot use a variable in range directive in shell i.e. {1..10} is fine but {1..$n} is not.

While using BASH you can use ((...)) operators:

for ((i=1; i<=count; i++)); do
   array[$i]=$(cut -d',' -f3 file.txt | sort -r | uniq | tail -n $i)
done

Also note removal of useless use of cat from your command.