refactor - make all changes to input arguments in parse_args
readability - indent few lines in if
refactor - replace_linear, replace_global - better variables names
tuned argument --count and /g modifier with -s pattern

if -s with modifier /g is passed, it's override -c argument, and make
all replacements that can be done
if neither /g modifier neither -c is not passed, assume -c = 1
if -c is passed and /g is missing, use given -c value
improvements to verbose mode and other messages
added debug mode

previous verbose mode is now debug mode, current verbose mode show only
how many replacements was done in file