Perl::Tutorial::HelloWorld - Hello World for Perl
#!/usr/bin/perl # # The traditional first program. # Strict and warnings are recommended. use strict; use warnings; # Print a message. print "Hello, World!\n";
Open a text editor, and type in the above program. Save it in a file named "hello". Then open a terminal window.
First ensure the file is given executable permissions:
chmod u+x hello
Then you can run the program using either of the following:
./hello perl hello
You should see it print "Hello, World!" to the console.
Every Perl program should start with a line similar to one of these:
#!/usr/bin/perl #!/usr/bin/env perl
or on Windows:
The first line is known as the "shebang line", and is used by UNIX-like systems to look up the path to the Perl interpreter.
Comments in Perl always start with a '#' character:
# This is a single-line comment. # This comment extends over two lines # to illustrate multi-line comments. print 'hello'; # And here is an inline comment.
Anything to the right of a '#' will be ignored.
Statements always end with a semicolon in Perl:
print 'hello'; print 'This statement extends over two lines because there is no semicolon on the first line.';
It is possible to have more than one statement on a single line, but generally this would not be very readable.
These two statements turn on the 'strict' and 'warnings' pragmas:
use strict; use warnings;
These are strongly encouraged for all Perl programs - they tell the Perl interpreter to check for programming errors like undeclared variables.
To print some output to the terminal, you can use the 'print' function:
print "Hello, World!\n";
In this case, the double-quoted string "Hello, World!\n" is being printed. You should see that the "\n" sequence does not appear on the console - it is used to mark the end of a line. Double-quoted strings can contain various other escape sequences.
Copyright (C) 2011 Copperly Ltd.
This documentation is free software; you can redistribute it and/or modify it under the same terms as Perl itself.