In a directory in Unix convert Tab Delimeted file to Comma delimeted

On Request from one of our reader here is a post to convert excel files into a comma delimeted file.

create shell script using following code. The script below will fetch all files with extension xls and convert tabs into comma and create a .csv file.

cd /applmgr/custom/inbound/data
for i in *.xls
do
echo $i
newfile=$i.csv
awk 'BEGIN {
        FS = "\t"
        OFS = ","
     }
     {
        $1 = $1
        for (i = 1; i <= NF; i++) {
           if ($i == "") {
              $i = "null"
           }
        }
        print $0
     }' $i > $newfile
done