Stress is a biological term which refers to the consequences of the failure of a human or animal body to respond appropriately to emotional or physical threats to the organism, whether actual or imagined.

The term “stress” was first used by the endocrinologist Hans Selye in the 1930s to identify physiological responses in laboratory animals. He later broadened and popularized the concept to include the perceptions and responses of humans trying to adapt to the challenges of everyday life.

It covers a huge range of phenomena from mild irritation to the kind of severe problems that might result in a real breakdown of health.

Where does it come from?

Both negative and positive experiences can lead to stress. Some common culprits are food, housing, freedom, health, or mobility.

Social issues can also cause stress, such as social acceptance, or relationship conflict, deception, or break ups, and major events such as birth and deaths, and divorce.

Life experiences such as poverty, unemployment, depression, heavy drinking , or insufficient sleep can also cause stress. Students and workers may face stress from examinations, group projects and project deadlines.

Effects of chronic stress

Long-term exposure to stress can lead to serious health problems such as:

  • Pain of any kind
  • Heart disease
  • Digestive problems
  • Sleep problems
  • Depression
  • Obesity
  • Autoimmune diseases

Techniques of stress management

There are several ways to tackle stress. Effective stress management involves learning to set limits and to say “No” to some demands that others make. The following techniques are known to have a good effect in the fight against stress:

  • Conflict resolution
  • Exercise
  • Getting a hobby
  • Meditation
  • Deep breathing
  • Relaxation techniques
  • Artistic Expression
  • Progressive relaxation
  • Stress balls
  • Natural medicine
  • Time management

Making it happen

There are many ways to cope with stress and its symptoms which should be used, since the condition is undeniably damaging.

Learning how to relax increases your ability to stay calm and collected under pressure.

Investing in your emotional life allows you to remain focused, flexible, and positive in bad times as well as good.

Managing stress is all about taking charge: taking charge of your thoughts, your emotions, your schedule, your environment, and the way you deal with problems.

Its up to you 😉

SSH με χρήση κλειδιών – Passwordless SSH

SSH με χρήση κλειδιών

Για να συνδεόμαστε σε ενα σύστημα με SSH χώρις να χρειάζετε να πληκτρολογούμε καθε φορά κωδικό(remote backup πχ), κανουμε τα παρακάτω :

  • Το  σύστημα απο το οποίο κάνουμε/ξεκινάμε την συνδεση θα αναφέρεται απο εδω κ στο εξης ως client.
  • Ομοίως το συστημα στο οποίο συνδεόμαστε θα αναφέρεται ως server.
  • Οι παρακάτω πληροφορίες λειτουργούν μόνο σε  OpenSSH.
  • Στο παράδειγμα χρησιμοποιούμε DSA keys. Αν θέλουμε RSA keys αντικαθιστούμε το  ‘rsa’ με ‘dsa’.
  • Για να πετύχει  η διαδικασία πρέπει να δωθούν οι εντολές σε Bourne-like κέλυφος (sh, ksh or bash)


  1. Στον  client εκτελούμε τις παρακάτω εντολές:
  1. $ mkdir -p $HOME/.ssh
  2. $ chmod 0700 $HOME/.ssh
  3. $ ssh-keygen -t dsa -f $HOME/.ssh/id_dsa -P ”

Αυτο θα μας δημιουργήσει 2 αρχεία,

1)      $HOME/.ssh/id_dsa (private key) και

2)      $HOME/.ssh/ (public key).

  1. Αντιγράφουμε το  $HOME/.ssh/ στον  server.
  2. Εκτελούμε τα παρακάτω στον server :
  1. $ cat >> $HOME/.ssh/authorized_keys2
  2. $ chmod 0600 $HOME/.ssh/authorized_keys2

Αναλόγως την έκδοση του που έχουμε OpenSSH ίσως να χρειαστούν και οι παρακάτω εντολές:

$ cat >> $HOME/.ssh/authorized_keys

$ chmod 0600 $HOME/.ssh/authorized_keys

  1. Ελέγχουμε την ορθή λειτουργία στον  client δοκιμάζοντας την σύνδεση με τον  server ώς εξής :
  1. $ ssh -i $HOME/.ssh/id_dsa server
  2. Host server
  3. IdentityFile ~/.ssh/id_dsa
  1. (Προεραιτικά) Προσθέτουμε τις παρακάτω γραμμές στο αρχείο $HOME/.ssh/config στον client:

Αυτο μας επιτρέπει να καλουμε το ssh χωρις την χρήση του διακόπτη –i και την διαδρομη του κλειδιού.πχ : ssh root@server

That’s all folks 😀