PKCE OAuth2 flow with public client in Bash

Just a simple bash script that can be used to redeem a access-token using a public OAuth2 client with PKCE

Installation

Copy oauth2.sh into /usr/bin folder or any path with executables and make it executable.

e.g Termux on Android:

cp oauth2.sh /data/data/com.termux/files/usr/bin/oauth2
chmod +x /data/data/com.termux/files/usr/bin/oauth2

Using it with ssh

The intention is to use this with sshpass to allow a neat integration with oauth2 pam modules, e.g. pam-oauth2. This can be done be simply adding this function into your shell of your choose profile configuration.

function sshoauth2() {
    sshpass -p $(oauth2 <CLIENT_ID> <AUTHORIZATION_URL> <TOKEN_ENDPOINT>) ssh $1
}

Then the following command can be executed in the terminal:

sshoauth2 ssh user@host