I am trying to install dropbox onto my Debian machine, and I saw the instructioncd ~ && wget -O - some website leading to the download of a tar file | tar xzf - But what I did was just typing thiswget -O - some website leading to the download of a tar fileand I got a lot of rubbish on my terminal. What does wget -O -means? Does it do any harm to my computer?
What is the meaning of wget -O -
wget
Take a look at the man page for wget.-O file   --output-document=file       The documents will not be written to the appropriate files, but all       will be concatenated together and written to file.  If - is used as       file, documents will be printed to standard output, disabling link       conversion.  (Use ./- to print to a file literally named -.)       Use of -O is not intended to mean simply use the name file instead       of the one in the URL; rather, it is analogous to shell redirection:       wget -O file http://foo is intended to work like        wget -O - http://foo > file; file will be truncated immediately, and       all downloaded content will be written there.So you can either download the contents of URL to a file using -O somefile or you can download it and redirect its contents via STDOUT to another tool to do something with it. In this case that's what they're doing with the | tar xvf -.Your command:$ cd ~ && wget -O - some website leading to the download of a tar file | tar xzf -The above is taking the tarball from the URL and as it's being downloaded it's being redirected to the command tar so that it can be unpacked into your filesystem.