Often some hosts in corporate network are available only from several gateway machines. The scheme looks like that: you connect to gateway
ssh -A gateway.public.net and then to desired host from gateway machines
ssh -A host.private.net. But the problem arises when you want to copy or download something from host.private.net. You have to do it in two hops, because host.private.net is not available from your machine directly. The solution is ssh forwarding. Just add the following (edit according your network settings) lines to
It is possible to save configuration of ssh connection for later usage. For example, one had to type
ssh <username>@<ip address> -p <port> -i <path to key file>
every time one wants to connect to server.
Pcap files are pocket capture files. They usually contain raw log of network connections and packets. It is the most popular format and it available in almost all network analysis tool.
To play around *.pcap, you have to get such file somehow. There are two opposite ways: to generate it by yourself or to pick a ready one. To generate it by yourself, you can use wireshark or tcpdump in terminal:
tcpdump -w capture.pcap -i eth1
replace “capture.pcap” with desired output filename, “-i eth1” indicates the interface for the logging to be done.
du (disk usage) utility in linux bash summarizes disk usage of each directory or file. By default, it outputs only directories. Just enter some dir and type
$ du ./
It’s quite an academic task, but anyway useful sometimes. I’ve collected different ways to do it in terminal in linux. Some of them work with UTF-8 characters (some it will toggle case for “й”, “ё” and so on. It will not in general handle special ligatures, such as “ß”” and “ﬁ”.)
Ways are: sed, perl, python, awk, tr, bash, dd.