IT 244: Introduction to Linux/Unix
Class 14

Today's Topics


Homework 7

I have posted homework 7 here.

It is not due this coming Sunday.

Instead is due on the Sunday of the following week, October 28th.

This is to allow you time this weekend to study for the mid-term.


The mid-term exam for this course will be held on Tuesday, October 23rd.

It will consist of 25 questions like those on the quizzes.

You will have the entire class period to work on the exam.

60% of the questions will come from the Ungraded Class Quizzes.

Today's class will be a review session.

You will only be responsible for the material in today's class on the exam.

The Mid-term is a closed book exam.

No Class Exercise or Class Quiz

Today is a review session.

There will no Class Exercise or Class Quiz today.


Correcting Mistakes on the Command Line

Retrieving Your Last Command Line Entry

Aborting a Running Program

Getting Help with Unix Commands

Special Characters

Quoting and Escaping

cd - Change Directory

pwd - Show Your Current Directory

ls - List the Contents of a Directory

cat - Print the Contents of a File

rm - Delete a File

mkdir - Create a Directory

rmdir - Delete a Directory

cp - Copy Files

mv - Move a File or Directory

echo - Print Text to the Terminal

Pagers - View a File One Screen at a Time

Pathname Completion

grep - Finding Strings inside Files

tail - View the Bottom of a File

sort - Print a File in Sorted Order

diff - Differences between Files

Pipes - Stringing Programs Together

date - Get the Date and Time

which - Finding a Program File

locate - Search for Any File

finger - Get information on Users

The Hierarchical Filesystem

Case Sensitivity

Filename Extensions

Current Directory

Your Home Directory

Hidden Filenames

The . and .. Directory Entries


Absolute Pathnames

Tilde ~ in Pathnames

Relative Pathnames

Relative Pathnames in Your Current Directory

Relative Pathnames in a Subdirectory

Relative Pathnames above the Current Directory

Relative Pathnames Neither above Nor below the Current Directory

Access Permissions

Viewing Access Permissions


Using chmod with Numeric Arguments

The root Account

Directory Access Permissions


Command Options

The PATH System Variable

Running a Program in the Current Directory

Standard Input, Standard Output and Standard Error

The Keyboard and Screen as Standard Input and Standard Output


Redirecting Standard Output

Redirecting Standard Input

Redirecting Standard Output Can Destroy a File

Adding Output to an Existing File