For-loops

for file in *.fq.gz; do
	echo $file  
done

If there are three .fq.gz files, the output is:

file1.fq.gz
file2.fq.gz
file27.fq.gz

Nested for-loop

for file in *.fq.gz; do
    for number in {1..2}; do
        echo $number; done  
done

If there are three .fq.gz files, the output is:

1
2
1
2
1
2