Universal Ctags doesn't directly support reading source code from standard input (stdin) to generate tags to standard output (stdout). Typically, Universal Ctags expects filenames as arguments and writes the output to a tags file or other specified file.

For a typical Linux setup, if you want to work with input and output redirection involving stdin and stdout with Ctags, you'd likely need to use a workaround, such as using temporary files or modifying how you handle file input and output in your scripts or tools that integrate with Ctags.