Alternatively, you can always use regexes. This is being silly, though.
perl -lane'sub f{s/^([^,]+),/$1|/} sub b{s/,([^,]+)$/|$1/} f;f;f;b;b;b;b; print' A/NSRLFile.txt
Like another commenter suggested, though, I'd use a module unless you really have a good reason not to.