If all you're trying to do is remove the periods then arguably the most appropriate tool (though as with most text manipulation tasks in bash not the only one) for the job is sed:
sed let's you use regular expressions to manipulate text in files or an output stream, so for instance:
echo $SYSIN | sed 's/\.//g'
The sed syntax used here has the form:
's(search and replace)/regex pattern to match/replacement/g(replace all matches, not just one)'
In the example I gave the period is escaped since otherwise periods match any character, and it replaces it with nothing (i.e. removes it).