it should be a short programm which is able to count all charaters in a file and put the result to antoher file.
If you are on Linux, you can just run
gcc -o "nameOfYourExcuteableFile" main.c
./nameOfYourExcuteableFile
You need to change the file paths in the C-code to run it on your system.
just run following command to see all usages:
./nameOfYourExcuteableFile -h