Process substitution in shells allows feeding the output of multiple commands into another command. Which command demonstrates this technique?

• A. It allows feeding the output of multiple commands into another command using <(command)
• B. It speeds up command execution by caching results
• C. It merges two command outputs into a single file
• D. It duplicates a command's output across multiple processes

Answer: (A)

Process substitution lets you feed the output of commands into another command by making each command’s output appear as a file-like path. Using the syntax <(command) creates a read-only handle that the receiving command can open as if it were a file. When you pass multiple such paths to a single command, it can read each command’s output as separate inputs without creating temporary files. This is exactly what the example shows: feeding the outputs of multiple commands into one command via <(command). The other choices describe caching, redirecting outputs to a single file, or duplicating output across processes, which do not capture the technique of turning command outputs into file-like inputs for another command.