The original cp(1) utility prints useful information when it receives a SIGINFO signal, as shown in the following output:
$ cp FileToCopy /tmp/copy FileToCopy -> /tmp/copy 26% FileToCopy -> /tmp/copy 29% FileToCopy -> /tmp/copy 31%
So, the rest of this section will implement the same functionality to the Go implementation of the cp(1) command. The Go code in this section will be based on the cp.go program because it can be very slow when used with a small buffer size giving us time for testing. The name of the new copy utility will be cpSignal.go and will be presented in four parts.
The fundamental difference between cpSignal.go and cp.go is that cpSignal.go should find the size of the input file and keep the number of bytes that have been written at a given point. Apart from those modifications there is nothing else that you should worry about...
