PERL HOWTO

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BASIC SYNTAX

Perl is case sensitive. Most code is typed in lowercase.
The syntax is in some part similar to C.

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TOP LINES

The following are recommended as first lines in Perl scripts:

#!/usr/bin/perl -wT
use strict;

with no white space or blank lines before the #!
The option -w gives warnings; 
The option -T checks security of cgi or suid/sgid scripts. 
The strict mode requires that variables are declared and makes debugging
easier.

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FILE EXTENSIONS

Under UNIX/Linux, file containing Perl scripts usually do not have 
any extension; on some occasions you see the extension .pl.

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RUNNING PROGRAMS

The program file needs to be made executable by
the following command, typed at the UNIX/Linux shell prompt:

	chmod u+x FILENAME

To execute a script, type 

    FILENAME 
    
at the shell prompt. 
To run the program this way, #!/usr/bin/perl or similar 
is required as a top line in the file.

Running the program will cause that its syntax is checked
and related messages displayed.

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CHECKING SYNTAX

To check the syntax in FILENAME without running the program,
type at the shell prompt:

	perl -c FILENAME
	
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ON-LINE HELP

Execute at the shell prompt:
	
	perldoc -f push  # Help on function push
	perldoc -m CGI::Carp # Source code of module CGI::Carp
	perldoc -q KEYWORD
    perldoc perlre # Help on reqular expression
    perldoc perldoc

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ON-LINE BOOKS

Look up on-line books "Learning Perl" and
"Perl Cookbook", following links from instructor's web page.