some article refresh (#21837)

* some article refresh

this had some misinformation in it (identifiers as hosts in SSH??) 
fixed it and added some basic information, why this tool is needed and replaced predecessor telnet
also some basic usage

* Update index.md
This commit is contained in:
David Abutbul
2018-11-17 19:24:42 +02:00
committed by Christopher McCormack
parent 944a9796d8
commit ee87987fa3

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@ -1,18 +1,20 @@
---
title: Bash ssh
title: Bash ssh (Secure SHell)
---
## Bash command: ssh
This command is used **to connect to a remote computer**, for example `ssh 123.456.789.012` will try to establish a connection with that host. The address of the remote computer can be provided using an IP address or, if provided, an identifier.
**Used to securly connect to a remote server** using Diffie-Hellman algorythm for key exchange, ssh replaces the archaic telnet program for remote shell sessions.
If the remote computer requires the user to login, they can use the form `ssh username@remote_address`, which will then prompt them for the user password on a successful connection.
for example `ssh 192.0.2.1` will try to establish a connection with that host. The
address of the remote computer can be provided using an IP address resolvable hostname or FQDN.
It also has command line options which can be found on the SSH website.
If you wish to use a different username then the one initiating the session (i.e. you're using ssh from root but wish to log in as different user to a remote system), the form `ssh username@remote_address` can be used, which will then prompt for the user password on successful connection.
One thing to note, if the server is configured to listen to any port other than `22`, then you have to use `-p` option to specify the port. For example: `ssh -p 2024 123.456.789.012`.
If the remote computer requires user login, the form `ssh username@remote_address` can be used, which will then prompt for the user password on successful connection.
Basic usage arguments:
- `-p` - use a different port then configured in ssh_config file (usually 22)
- `-u` - pass username outside of hostname URI
- `-i` - use a different location for private key
### More Information:
* [Wikipedia](https://en.wikipedia.org/wiki/Secure_Shell)