Lecture 3 Notes, CSCI 2132.pdf

Lecture 3 Notes, CSCI 2132.pdf - Lecture 3 Notes CSCI 2132...

Info icon This preview shows pages 1–2. Sign up to view the full content.

3/31/2018 Lecture 3 Notes, CSCI 2132 1/3 Lecture 3, CSCI 2132 Input, Output and Error Channels There are three default I/O channels in a UNIX system: stdin (standard input) stdout (standard output) stderr (standard error) In UNIX, a program reads input from stdin, writes its output to stdout and writes error messages to stderr. By default, all three channels are the terminal running the program or command. Later we will learn how to use a mechanism called redirection to change the default I/O channels of a program. Getting Help Online: man There is a UNIX command called man that can be used to get the manual page about a command or a system function. There are two ways of running man. The syntax of the explicit way is man command-name This can be used to get the manual page of the command "command-name". Some examples are man clear man man You can also specify a keyword and ask man to give a list of programs that fit the keyword, together with a short description of each program. You can then look for the program that performs the task that you would like to perform, and use man in the explicit way to find out how to use the program. The syntax is man -k keyword An example: man -k password Special Characters (Metacharacters) Special characters are characters that are interpreted specially when typed at a UNIX terminal. Here we will learn two of them.
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

Image of page 2
This is the end of the preview. Sign up to access the rest of the document.
  • Winter '12
  • MengHe
  • directory structure, default I/O channels

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern