echo "enter choice to combine files:"
echo "1)verically"
echo "2)horizotally"

read ch
case $ch in
1) cat m1 > emp3
   cat m2 >> emp3;;
2) paste m1 m2 >> emp4;;
*) ;;
esac


OUTPUT
***********

[04mca58@LINTEL 04mca58]$ sh combine.sh
enter choice to combine files:
1)verically
2)horizotally
1
[04mca58@LINTEL 04mca58]$ cat emp3
thisis m1
thisis m2
[04mca58@LINTEL 04mca58]$ sh combine.sh
enter choice to combine files:
1)verically
2)horizotally
2
[04mca58@LINTEL 04mca58]$ cat emp4
thisis m1      thisis m2