Can we have a linux terminal chat client for gmail

The "group chats" are a nonstandard feature, incompatible with XMPP multi-user chats, and can only be created using the Talk gadget in Gmail.

Try my other suggested method first, because once you reset your password, you won't get back the old one.

If you can get to the gmail web interface, and it sounds like you can, then you should be able to add a recovery email address to your account.

Go to the gmail web interface, click the account drop-down (it'll be your name or username, near the top right), and choose "account settings."

This will take you to the Google Accounts page. Under the "email addresses and usernames" section, you should be able to click "edit" and add a new email address to your account. Use a non-gmail address. It sounds like you lost some other accounts too, so you may need to create a new yahoo, hotmail, or other such account. Don't use anything like mailinator since somebody else could get access to your account.

Once you add the secondary email address, you'll need to confirm it by checking that email address. Confirm the address. Now, go open a new browser session (different browser, incognito mode, other computer - whatever). Go to gmail.com, and click on "can't access your account." This will take you to a form where you should be able to send a reset link to your alternate email (which you just added).

Once you receive the reset email, you'll be able to choose a new password, and should have full access to your email again!