Perl

Tom Kelliher, CS 318

Jan. 21, 1999

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Assignment

Find three Perl resources on the Web and e-mail the URLs to me by 1:20pm on 1/24/00.

From Last Time

Threw around some course structure ideas.

Outline

1. Perl: mechanics, variables, control, I/O, subroutines.

2. Perl lab.

Coming Up

More Perl.

Perl Mechanics

1. Phoenix accounts.

2. Editing.

3. Perl file extension: .pl.

4. Making a Perl script executable: chmod.

5. Documentation and readability.

6. The ``magic'' line:

   #!/usr/local/bin/perl -w
   

   Why -w? Debugging help

7. use strict; and my. Global vs. local variables.

Variables

1. Scalars.

2. Arrays/Lists. ``Length.'' Indexing as a scalar.

Control

1. Blocks. Scoping.

2. Conditions.

3. If/Else. Elsif.

4. While, for.

I/O

1. STDIN, STDOUT, STDERR.

2. Open(), close(), file handles.

3. Line input with <FILEHANDLE>

4. getc [FILEHANDLE]

Subroutines

1. Prototype declaration.

2. Definition:

   sub foo
   {
   ...
   }
   

3. Parameter ``passing.''

4. Parameter list in @_.

5. Get next parameter:

   $foo = shift(@_);
   

Lab

Add a subroutine to cat.pl.