wc-tool in go

trying to implement wc-tool in go, part of this challenge: https://codingchallenges.fyi/challenges/challenge-wc

build:

go build

run:

1. bytes count

./wc-tool-go wc -c test.txt
342190 test.txt

2. lines count

./wc-tool-go wc -l test.txt
7145 test.txt

3. words count

./wc-tool-go wc -w test.txt
58164 test.txt

4. char count

./wc-tool-go wc -m test.txt
339292 test.txt

5. no options

./wc-tool-go wc test.txt
7145  58164  342190 test.txt

6. reading from stdin if no file is specified

cat test.txt | ./wc-tool-go wc
7145  58164  342190