For loop function doesn't work within a while loop - bash

Question

I am looking to repeat the same function for each gene in my genelist. This is what the while loop does. Then it extracts the files from the master document into a new bed file.
The number_of_lines variable is the number of rows in the document. And I want to create a document with the number of row corresponding to number_of_lines
i.e.
number_of_lines=1
output
1
number_of_lines=5
output
5
5
5
5
5
my code below
while read gene
do
grep -w $gene $masterfile | awk '{print $1"\t"$2"\t"$3"\t"$5"\t"$6"\t"$4}' > $gene.bed
number_of_lines=$(grep "^.*$" -c $gene.bed)
echo $number_of_lines
cat "" > $gene.1.bed
for i in 'eval echo {1..$number_of_lines}'
do
echo $number_of_lines >> $gene.1.bed
done
done < $genelist
if I do this by itself
cat "" > $gene.1.bed
for i in 'eval echo {1..$number_of_lines}'
do
echo $number_of_lines >> $gene.1.bed
done
it works?

Answer 1

You need to put eval echo {1..$number_of_lines} inside $() to expand to the output.
cat "" will get an error, that should be echo "". But simpler is to just put the output redirection around the entire loop instead of after each echo statement.
while read gene
do
grep -w "$gene" "$masterfile" | awk '{print $1"\t"$2"\t"$3"\t"$5"\t"$6"\t"$4}' > "$gene.bed"
number_of_lines=$(grep "^.*$" -c "$gene.bed")
echo $number_of_lines
for i in $(eval echo {1..$number_of_lines})
do
echo $number_of_lines
done > "$gene.1.bed"
done < "$genelist"

Answer 2

When you see eval, you "know" your code is wrong. #Barmar already pointed out the normal construction for ((i=0; i<$number_of_lines; i++)), what should be used here. With all lines having the same content, you have another possibility: yes. I made some other changes too.
while read gene
do
grep -w "${gene}" "${masterfile}" |
awk 'BEGIN {OFS="\t";} {print $1, $2, $3, $5, $6, $4}' > "${gene}.bed"
number_of_lines=$(wc -l < "${gene}.bed")
echo "${number_of_lines}"
yes "${number_of_lines}" | head -"${number_of_lines}" > "${gene}.1.bed"
done < "${genelist}"