Redirection (computing)
In computing, redirection is a function common to most command-line interpreters, including the various Unix shells that can redirect standard streams to user-specified locations.
In unix-like operating systems programs do redirection with the dup2(2) system call, or its less-flexible but higher-level stdio analogues, freopen(3) and popen(3).
Read more about Redirection (computing): Redirecting Standard Input and Standard Output, Piping, Redirecting To and From The Standard File Handles, Chained Pipelines, Redirect To Multiple Outputs