sed is a linux command that can replace characters and words in a file very easy! Syntax: sed -i ‘s/word/newword/g’ file.txt It means: replace all “word” with “newword” in the file called “file.txt”. Be aware! The option -i means that you will manipulate the file file.txt on-the-fly! If you are not sure, skip the -i

Sometimes you like to know some more what is behind a web-address or a domain-name. Then the linux command ‘dig’ can be helpful: dig www.interstingwebsite.com soa Example: dig www.google.com soa which gives:  ]$ dig www.google.com ; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.10.rc1.el6_3.5 <<>> www.google.com ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: