docgen: command not found

[CassandraCat]

I use

curl https://raw.githubusercontent.com/thedevsaddam/docgen/v3/install.sh -o install.sh \                                                                                                       
&& sudo chmod +x install.sh \
&& sudo ./install.sh \
&& rm install.sh

Then the command line shows

Found docgen latest version:
Download may take few minutes depending on your internet speed
Downloading docgen to /usr/local/bin/docgen
Installing docgen
Installation complete
./install.sh: line 29: docgen: command not found

Unable to install successfully, what is the reason？