gistfile1.txt

while read line
do
    srr=$line
    numLines=$(fastq-dump -X 1 -Z --split-spot $srr | wc -l)
    if [ $numLines -eq 4 ]
    then
    echo "$srr,single_end" 
    echo "$srr,single_end" >> file.log
    else
    echo "$srr,paired_end" 
    echo "$srr,paired_end" >> file.log
    fi
done <  /Users/admin/accession_N146_single_end.list