Running Perl scripts from a file in linux

Question

I'm in Linux (CentOS) trying to run a basic Perl script from a file. I am getting an error. I think it has something to do with the syntax, but I can't figure it out.

$ perl -e 'print "Hello World\n";'

This runs fine and will print Hello World on the next line. However, when I put this into vi and save it as perlOne, exactly the same (perl -e 'print "Hello World\n";') and run the command:

$ perl perlOne

I get the error: "syntax error at perlOne line 1, near "perl -e -- Execution of perlOne aborted due to compilation errors."

It's the same line, but it does not work in the file.

I'm working through the Perl tutorial from Linux Pro Magazine - which is where I got this from.

Answer 1

The command-line switch -e allows you to run code from the command line, instead of having to write your program to a file and then execute it.

$ perl -e 'print "Hello World\n";'

Output:

Hello World

If you want to run it from your file you will need to write it differently:

#!/usr/bin/perl

use strict;
use warnings;

my $message = 'Hello World';
print $message . "\n";

# You can also make it directly
print "Hello World\n";

While I do not recommend it can also be written as:

print "Hello World\n";