# Working with multiple SSH keys
## Step 1. Ensure you have an SSH client installed
```
ssh -V
ls -a ~/.ssh 
```
## Step 2. Set up your identity
You can create a default identity 
```
$ ssh-keygen 
Generating public/private rsa key pair.
Enter file in which to save the key (/Users/username/.ssh/id_rsa):
----
Enter passphrase (empty for no passphrase):
```

You can create multiple SSH identities with this three ssh- commands:

| SSh Command | Purpose |
|-------------|:-------------:|
| ssh-keygen | Create keys pairs |
| ssh-agent | Agent for proving keys to remote servers. The agent holds loaded keys in memory |
| ass-add | Loads a private key into the agent |

### Create multiple identities
```
ssh-keygen -t rsa -f ~/.ssh/personalid -C "personalid"

'-t' force pseudo-terminal allocation.
'-f' requests ssh to go to background just before command execution.
'-C' requests compression of all data.
```
```
$ ssh-keygen -t rsa -f ~/.ssh/personalid -C "personalid"
Generating public/private rsa key pair.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /Users/username/.ssh/personalid.
Your public key has been saved in /Users/username/.ssh/personalid.pub.
The key fingerprint is:
7a:9c:b2:9c:8e:4e:f4:af:de:70:77:b9:52:fd:44:97 personalid
The key's randomart image is:
+--[ RSA 2048]----+
|         |
|         |
|        .|
|        Eo|
|  .  S  . ..|
|  . . o . ... .|
|  . = = ..o o |
|  . o X ... . .|
|  .ooB.o ..  |
+-----------------+
```
### Create a SSH config file
When you have multiple identity files, creating a SSH config file allows you to create aliases for your various identities.
The format for the alias entries used is:
```
Host alias 
HostName github.org 
IdentityFile ~/.ssh/identity
```
1. Edit the `~/.ssh/config` file
2. Add an alias for each identity combination
```
Host github-workid
 HostName github.org
 IdentityFile ~/.ssh/workid
Host github-personalid
 HostName github.org
 IdentityFile ~/.ssh/personalid
```
### Load each key into appropiate Host account
Copy your specific public key (`.pub`)
```
cat ~/.ssh/id_rsa.pub
```
```
pbcopy < ~/.ssh/id_rsa.pub
```

## Step 3. ssh-agent
### Ensure the ssh-agent is running and loaded with your keys
1. Check if the process is already running: 
```
ps | grep ssh-agent
----
$ ps | grep ssh-agent
4013 ttys001    0:00.00 grep ssh-agent
```
- If not run `ssh-agent`.
- If there is more than 1 process running use `kill PID` command to stop each of them. Then restart a single instance.
2. List the currently loaded keys: 
```
ssh-add -l
```
3. If necessary, add your new key to the list:
```
ssh-add ~/.ssh/personalid
----
$ ssh-add ~/.ssh/personalid
Enter passphrase for /Users/username/.ssh/personalid:
Identity added: /Users/username/.ssh/personalid
```
4. List the keys again to verify the add was successful: 
```
ssh-add -l
```

## Step 4. Repositories
### Clone git repository 
1. Using the default key: `git clone git@github.com:username/project.git`
2. Using a specific key: ` git clone git@personalid:username/project.git` (`git@personalid:iarroyo5/project.git`)

## Step 5. known_hosts
Remove entries from known_hosts:
```
ssh-keygen -R hostname
```