You compare a file against itself ?
The if condition is wrong syntax, in bash you simply do :
if /usr/bin/cmp $file1 $file2; then
echo files match
or if you don't need action if files match...
# if files don't match
if ! /usr/bin/cmp $file1 $file2; then
# do action
Also, better add full program path if using the script with cron, just in case