I won't recommend you ssh-add (which need to open a ssh-agent) at login. This is because you can't control when the ssh-agent section ends, and can create security risk when you need not use the keyfiles at one login section.

Rather, I recommend to write a script which opens a ssh-agent's section sub-shell, with all keyfiles auto added, and be called when needed to use ssh. If you could adopt so, read on.

You would have two choices:

1. Remove all passphrases for your keys, which have weak security if your key files are stolen. (thus not recommended)

2. Use the same passphrase for your keys. Then when you ssh-add keyfile1 keyfile2 ..., you will only need to type the passphrase once, per section.

In both cases, you could write such script file "ssh_keys_section.sh" as below:

#!/bin/bash
# This script run a ssh-agent on a sub-shell and automatically ssh-add all keyfiles at once.
# This agent ends when you type `exit` to close the sub-shell.
exec ssh-agent bash -c "ssh-add /path/to/keyfile1 /path/to/keyfile2 ...; exec bash"

Reference:

• Command to change or delete passphrase: ssh-keygen -p -f keyfile

I won't recommend you ssh-add (which need to open a ssh-agent) at login. This is because you can't control when the ssh-agent section ends, and can create security risk when you need not use the keyfiles at one login section.

Rather, I recommend to write a script which opens a ssh-agent's section sub-shell, with all keyfiles auto added, and be called when needed to use ssh. If you could adopt so, read on.

You would have two choices:

1. Remove all passphrases for your keys, which have weak security if your key files are stolen. (thus not recommended)

2. Use the same passphrase for your keys. Then when you ssh-add keyfile1 keyfile2 ..., you will only need to type the passphrase once, per section.

In both cases, you could write such script file "ssh_keys_section.sh" as below:

#!/bin/bash
# This script run a ssh-agent on a sub-shell and automatically ssh-add all keyfiles at once.
# This agent ends when you type `exit` to close the sub-shell.
exec ssh-agent bash -c "ssh-add /path/to/keyfile1 /path/to/keyfile2 ...; exec bash"

Remarks:

• Command to change or delete passphrase: ssh-keygen -p -f keyfile
• Within the sub-shell, you might even fork more terminals which share the same unlocked keys, by using maybe a command like /path/to/yourterminal & (depends on OS)