Passing bash variable into inline perl script

Question

Reference the 2nd to last line in my script. For some reason Perl is not able to access the variable $perlPort how can I fix this? Note: $perlPort is a bash variable location before my perl script

perl -e '
{
    package MyWebServer;
    use HTTP::Server::Simple::CGI;
    use base qw(HTTP::Server::Simple::CGI);
    my %dispatch = (
        "/" => \&resp_hello,
    );


    sub handle_request {
        my $self = shift;
        my $cgi  = shift;
        my $path = $cgi->path_info();
        my $handler = $dispatch{$path};
        if (ref($handler) eq "CODE") {
            print "HTTP/1.0 200 OK\r\n";
            $handler->($cgi);
        } else {
            print "HTTP/1.0 404 Not found\r\n";
            print $cgi->header,
            $cgi->start_html("Not found"),
            $cgi->h1("Not found"),
            $cgi->end_html;
        }
    }


    sub resp_hello {
        my $cgi  = shift;   # CGI.pm object
        return if !ref $cgi;
        my $who = $cgi->param("name");   
        print $cgi->header,
            $cgi->start_html("Hello"),
            $cgi->h1("Hello Perl"),
            $cgi->end_html;
    }
}


my $pid = MyWebServer->new($perlPort)->background();
print "Use 'kill $pid' to stop server.\n";'

In the same way you wrote 'kill $pid' why you don't write '$perlPort'? — Casimir et Hippolyte
– Casimir et Hippolyte, Commented Oct 29, 2016 at 21:08

Ole Tange · Accepted Answer · 2016-10-29 22:30:58Z

5

export perlPort
perl -e '
...
my $pid = MyWebServer->new($ENV{perlPort})->background();
'

answered Oct 29, 2016 at 22:30

Ole Tange

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Comments

ernix · Accepted Answer · 2016-11-01 04:30:01Z

2

You can use -s switch to pass variables. See http://perldoc.perl.org/perlrun.html

perl -se '
...
my $pid = MyWebBrowser->new($perlPort)->background();
...' -- -perlPort="$perlPort"

answered Nov 1, 2016 at 4:30

ernix

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Comments

chepner · Accepted Answer · 2016-10-30 02:31:20Z

You can still pass command line arguments to your script. Replace $perlPort with $ARGV[0], then call you script as

perl -e $' ...
         my $pid = MyWebServer->new($ARGV[0])->background();
         print "Use \'kill $pid\' to stop server.\n";' "$perlPort"

Note the other problem: You can't include single quotes inside a single-quoted string in bash. You can work around this by using a $'...'-quoted string as the argument to Perl, which can contain escaped single quotes. If your script doesn't need to read from standard input, it would be a better idea to have perl read from a here-document instead.

perl <<'EOF' "$perlPort"
{
package MyWebServer;
use HTTP::Server::Simple::CGI;
...
my $pid = MyWebServer->new($ARGV[0])->background();
print "Use 'kill $pid' to stop server.\n";
EOF

The best idea is to simply use a script file instead of trying to construct the script on the command line.

V. Michel · Accepted Answer · 2016-10-29 21:52:50Z

0

perl -e '
   ...
my $pid = MyWebServer->new('$perlPort')->background();
   ...

answered Oct 29, 2016 at 21:52

V. Michel

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1 Comment

chepner Over a year ago

Unquoted parameter expansions are subject to word-splitting and pathname expansion. The intended value (an integer) is safe, but this is fragile.

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