Comparing String with Number variables

Shell Programming and Scripting
1

I have two variables and want to perform some functions after comparison

$cat file1
14.abcde
 
a=`cut -f 1 -d "." file1
b=15
 
if [ $a -lt $b ] 
then
   ....
fi

but i got an error message says that unary operator expected
and i think its because of $a is a string and trying to compare with integer variable.

Can someone help me to fix this ??

2 
#!/bin/ksh

b=15

while IFS=. read num rest
do
   if [ "${num}" -lt "${b}" ]; then
      printf "%d < %d\n" "${num}" "${b}"
   fi
done < file1
3

Never Mind.
I solved it Thanks

4 
a=`echo "14.abcde" | cut -f 1 -d "."`
b=15
if [ $a -lt $b ]
then
echo "less"
fi

cheers,
Devaraj Takhellambam