Earth Info

2) SSH config

Of course I set up ssh with keys so I can log into each machine without needing to specify a password. To do this, create the keys on your workstation

ssh-keygen -t rsa

I don’t use any pass phrase as this slows everything down, and I rely on my workstation being secure. Next, is to copy the contents of the public key you just created

~/.ssh/id_rsa.pub

and paste it into a file on the remote server called

~/.ssh/authorized_keys

I also set up a file on my workstation named ~/.ssh/config which saves you specifying options on the command line for scp and ssh.

Host *
Compression yes
CompressionLevel 9
KeepAlive yes

host      strawberry
user      root
hostname  123.123.123.125
port      3366

host      banana
user      root
hostname  123.123.123.124
port      3366

This allows you to pre-configure access to the machines via ssh and specify some options you want to use each time. In my case I put all my machines SSH daemon on a non standard port (3366) for security, and I always log in as root. This config file  is also used for scp, so to copy machines from my workstation to the remote server it’s simply

scp index.html strawberry:/var/www/httpdocs/

3) Aliases

I guess you could do this with a script but I opted to do it via aliases. In you shell startup scripts (possibly ~/.bashrc or perhaps bashrc refers to an alias file called ~/.bash_aliases) I alias each machine name with

alias strawberry="ssh strawberry"

So to connect to a machine I simply type in its name. In addition to this, each of my web sites base  (which are setup using Plesk), location is something like /var/www/vhosts/mydomain.com/httpdocs. So I create an alias named from an abbreviation of the website such as alias md=’cd /var/www/vhosts/mydomain.com/httpdocs’ alias ad=’cd /var/www/vhosts/anotherdomain.com/httpdocs’ So once I connect to a machine, I can nvaigate into the correct directory in a few keystrokes by just type “md” or “ad”

4) Coloured Promtps

As I look after lots of machines, you really don’t want to be typing the wrong thing into the wrong machine. So I colour code the prompts by adding something like this to .bashrc on each server

STARTCOLOUR='\[\033[1;36m\]'
ENDCOLOUR='\[\033[40;0;37m\]'
PS1="${USER}@$STARTCOLOUR${HOSTNAME}$ENDCOLOUR:\w> "

Change the number 36 to another colour code for each machine, here is a list of the available colours Foreground Colours

• 30 Black
• 31 Red
• 32 Green
• 33 Yellow
• 34 Blue
• 35 Magenta
• 36 Cyan
• 37 White

The colours really stop you making silly mistakes.

5) Concurrent execution of commands

If you need to do the same thing on multiple machines try cssh. Once installed use,

cssh server1 server2 server3...

An ssh terminal will appear for each server and another control window. With the control window in focus anything you type will be inserted into all ssh terminals, plus you canswitch focus to an individual terminal and just send characters to that specific machine.