usage: ssh-keygen [-q] [-b bits] [-t dsa | ecdsa | ed25519 | rsa]
[-N new_passphrase] [-C comment] [-f output_keyfile]
ssh-keygen -p [-P old_passphrase] [-N new_passphrase] [-f keyfile]
ssh-keygen -i [-m key_format] [-f input_keyfile]
ssh-keygen -e [-m key_format] [-f input_keyfile]
ssh-keygen -y [-f input_keyfile]
ssh-keygen -c [-P passphrase] [-C comment] [-f keyfile]
ssh-keygen -l [-v] [-E fingerprint_hash] [-f input_keyfile]
ssh-keygen -B [-f input_keyfile]
ssh-keygen -D pkcs11
ssh-keygen -F hostname [-f known_hosts_file] [-l]
ssh-keygen -H [-f known_hosts_file]
ssh-keygen -R hostname [-f known_hosts_file]
ssh-keygen -r hostname [-f input_keyfile] [-g]
ssh-keygen -G output_file [-v] [-b bits] [-M memory] [-S start_point]
ssh-keygen -T output_file -f input_file [-v] [-a rounds] [-J num_lines]
[-j start_line] [-K checkpt] [-W generator]
ssh-keygen -s ca_key -I certificate_identity [-h] [-U]
[-D pkcs11_provider] [-n principals] [-O option]
[-V validity_interval] [-z serial_number] file ...
ssh-keygen -L [-f input_keyfile]
ssh-keygen -A
ssh-keygen -k -f krl_file [-u] [-s ca_public] [-z version_number]
file ...
ssh-keygen -Q -f krl_file file ...

ssh-keygen -t rsa -f ~/.ssh/id_rsa.github -C "zhangkui305@163.com"
ssh-keygen -t rsa -f ~/.ssh/id_rsa.gitlab -C "zhangkui305@163.com"

Generating public/private rsa key pair.
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /Users/longxiang/.ssh/id_rsa.github.
Your public key has been saved in /Users/longxiang/.ssh/id_rsa.github.pub.
The key fingerprint is:
SHA256:ocviE32+0q4aDMpT7BV+Lbog02K0Xm7WVBjj2IkhBrE zhangkui305@163.com
The key's randomart image is:
+---[RSA 2048]----+
|+.               |
| + . o           |
|E . *.= .        |
|  .o.=.o..       |
| ..o +ooS.       |
|o.=ooo+.o        |
|.O =*oo+         |
|o B+o+o o        |
| .o.o+.+o.       |
+----[SHA256]-----+

├── id_rsa.github
├── id_rsa.github.pub
├── id_rsa.gitlab
├── id_rsa.gitlab.pub

#github
Host github
Hostname github.com
user user@github.com
IdentityFile ~/.ssh/id_rsa.github
#gitlab
Host gitlab
Hostname gitlab.com
user user@gitlab.com
IdentityFile ~/.ssh/id_rsa.gitlab
#gitee 
Host gitee
Hostname gitee.com
user user@gitee.com
IdentityFile ~/.ssh/id_rsa.gitee

ssh-add ~/.ssh/id_rsa.github

ssh -T git@gitee.com
The authenticity of host 'gitee.com (212.64.62.174)' can't be established.
ECDSA key fingerprint is SHA256:FQGC9Kn/eye1W8icdBgrQp+KkGYoFgbVr17bmjey0Wc.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'gitee.com,212.64.62.174' (ECDSA) to the list of known hosts.
Hi 逐风! You've successfully authenticated, but GITEE.COM does not provide shell access.

git clone git@gitee.com:jiodg45/mutli_ssh_test.git