Tar and untar files.

You need to use the tar command as follows (syntax of tar command):
tar -zcvf archive-name.tar.gz directory-name
Where,

• -z : Compress archive using gzip program
• -c: Create archive
• -v: Verbose i.e display progress while creating archive
• -f: Archive File name

For example, say you have a directory called /home/jerry/prog and you would like to compress this directory then you can type tar command as follows:
$ tar -zcvf prog-1-jan-2005.tar.gz /home/jerry/prog
Above command will create an archive file called prog-1-jan-2005.tar.gz in current directory. If you wish to restore your archive then you need to use the following command (it will extract all files in current directory):
$ tar -zxvf prog-1-jan-2005.tar.gz
Where,

• -x: Extract files

If you wish to extract files in particular directory, for example in /tmp then you need to use the following command:
$ tar -zxvf prog-1-jan-2005.tar.gz -C /tmp
$ cd /tmp
$ ls -

Kevin Slavin: How algorithms shape our world

Ricardos law of rent working.

Ricardian rent or the Law of rent

The Law of Rent states that the rent of a land site is equal to the economic advantage obtained by using the site in its most productive use, relative to the advantage obtained by using marginal (i.e., the best rent-free) land for the same purpose, given the same inputs of labor and capital[

Essentially this means that the bargaining power of the renter can never dip below the produce obtainable on the best available rent-free land, because whenever rent leaves them with less than they could get on that free land, they can simply move to the new location.
So in essence if the rent is too low it will be bid up by those who can make better use of the land, whilst those areas where the rent is to expensive will become vacant.
 Land and properties that are vacant for a long time are simply priced above what the local market can stand.

Simples.

• The right tool for the right job, but don’t use 1000 tools. 
• The art of scaling is getting done what needs to be gotten done, while staying as close to statelessness as possible, without introducing unneeded complexity by doing so.
• Hardware vendors lie, appliance vendors lie. SSDs are great, but will not save you. Vendor lock-in is the anti-scale.
• The thing is, the key to the whole thing is that finest granularity of locking. Once you have a lock deep down in your system, your whole system is a locked system. This "lock" is not a thread-lock, it could be a cross-shard-join, it is anything that is not inherently scalable. 

  
High scalability and the art of Scaling

Find the current path in Linux/nix

To find the current path in Linux/nix simply type 'pwd'.

Richard Koo: Balance sheet recession explained.

The rat race.