terminal command not found
terminal opens in zsh , if I try to run command ls , clear , etc. it shows command not found.
Zsh shell does not read your old Bash dotfiles and you need to minimally configure a Zsh dot file (e.g. ~/.zshrc) to show a PATH statement. That ~/.zshrc file is not created for you, you must create that plain text dot file yourself with these contents:
export PATH=".:${PATH}"
Save the ~/.zshrc file and in your Terminal, run this command:
source ~/.zshrc
to make the PATH available to the current Terminal session.
The PATH will contain /usr/bin and /bin so that you can access the ls(1) and clear(1) commands. There is no clean command.