IT 244: Introduction to Linux/Unix
Class 19

Today's Topics

Tips and Examples


New Material

Homework 6

I have posted Homework 6 here.

As usual, it will be due next Sunday at 11:59 PM.


Tips and Examples

Using Control Z with an Editor


Separating and Grouping Commands

| (pipe) and & (ampersand) as Command Separators

Continuing a Command onto the Next Line

Using Parentheses, ( ) , to Run a Group of Commands in a Subshell

The Directory Stack

dirs - Displays the Directory Stack

pushd - Pushes a Directory onto the Stack

popd - Pops a Directory off the Stack

Shell Variables

Creating a Shell Variable


Local Variables

Global Variables

Choosing the Scope of a Variable

Defining Global Variables

Keyword Shell Variables

Important Keyword Shell Variables

User-created Variables

env - Show All Global Variables

New Material

Positional and Special Parameters

Quoting and the Evaluation of Variables

Removing a Variable's Value

Variable Attributes


System Calls

The History of Computer Languages

Creating a New Process

How the Shell Runs a Program

Process Structure

Booting a Unix Machine

Process Identification


Class Quiz