Shell Programming and Scripting

Error : more than 1 File found starting with increment 1, script aborted

ls -la

chk_file(){
RC=0
[[ ! -f "$1" ]] && echo "File missing: $1" && RC=1
return $RC
}
i=1
while [ $i -lt 100 ]
do
# if [ $(ls $i.* | wc -l 2>/dev/null) -gt 1 ]
if [ $((ls $i.* | wc -l) 2>/dev/null) -gt 1 ]
 
then
echo "Error : more than 1 File found starting with increment $i, script aborted"
exit 1
fi
# filename=$(ls $i.*)
 
filename=$((ls $i.*) 2>/dev/null)
echo "$filename is the filename"
# filename2=$(ls *Fe.ok | tail -1)
filename2=$((ls *Fe.ok | tail -1) 2>/dev/null)
echo "$filename2 is the filename"
# chk_file "${filename}" || break
# chk_file "${filename2}" || break
chk_file "${filename}"
#chk_file "${filename2}"
# cp "${filename}" "${filename2}" /usr/dob
ERROR1=$?
 
if [ ! ${ERROR1} -eq 0 ]
then
echo "Error , FILES NOT AVAILABLE TO COPY"
# break
else
cp "${filename}" "${filename2}" /usr/dob
 
echo "PROCESSING $filename and $filename2"
/usr/dob/my_script.ksh
echo "$filename completed......"
fi
ERROR=$?
 
if [ ! ${ERROR} -eq 0 ]
then
echo "Error from /usr/dob/my_script.ksh"
break
fi
let i+=1
done

1.L_D1.txt
3.L_ND.txt
5.L_D4.txt
14.L_ND4.txt
Fe.ok
EXECUTE123.ksh (This is our above script given by @ctsgnb)

if [ $((ls $i.* | wc -l) 2>/dev/null) -gt 1 ]

then

if [ $((ls $i.* | wc -l) 2>/dev/null) -gt 1 ]
then