Yes, you are 100% right, it does create a sparse file. I must have not run du or not at the right moment in the past. I also normally truncate first but it did not always seem to have the desired...
Not usually. Most UNIX filesystems have 'sparse' files... You can open a new file, seek ahead 99 gigabytes, and write 1 byte there, to get a file that looks like 99 gigabytes in ls, but only takes...
Ok, lets take it one column at a time:
Proto is the protocol used. tcp and udp should be pretty self-explanatory. icm is short for ICMP, which is a network control protocol (pings use ICMP...