HP-Certified HP-UX System Administration

Chapter 4. Input/Output Redirection and Pipes

Chapter Syllabus

• 4.1 Redirecting Standard Output

• 4.2 Redirecting Standard Input

• 4.3 Redirecting Standard Error

• 4.4 Redirecting Standard Input, Output, and Error Simultaneously

• 4.5 Pipes and How They Are Used

• 4.6 The T-Junction

Most UNIX commands are designed to take simple text (alphanumeric) data and punctuation as input. Usually, the output is also of simple text. Whenever you start a UNIX command, it opens three standard data streams: standard input (stdin), standard output (stdout), and standard error (stderr). Every UNIX command takes input data from stdin and sends its normal output to stdout and error messages to stderr. These data streams are often called standard input/output. UNIX associates numbers ...