This Perl code removes commas at the end of the line:
perl -pe 's/,$//' file > file.nocomma
This variation still works if there is whitespace after the comma:
perl -lpe 's/,\s*$//' file > file.nocomma
This variation edits the file in-place:
perl -i -lpe 's/,\s*$//' file
This variation edits the file in-place, and makes a backup file.bak
:
perl -i.bak -lpe 's/,\s*$//' file