shell
The detected shell type of the Terminal. This will be undefined when there is not a clear signal as to what the shell is, or the shell is not supported yet. This value should change to the shell type of a sub-shell when launched (for example, running bash inside zsh).
Note that the possible values are currently defined as any of the following: 'bash', 'cmd', 'csh', 'fish', 'gitbash', 'julia', 'ksh', 'node', 'nu', 'pwsh', 'python', 'sh', 'wsl', 'zsh'.