how to run piece of code just before the exit of perl script
There's two different ways to do this, depending on what you're looking for.
- The
END
block is executed when the interpreter is shut down. See the previous answer for more details :) - The
DESTROY
block/sub, that is executed when your object goes out of scope. That is, if you want to embed your logic into a module or class, then you can useDESTROY
.
Take a look at the following example (it's a working example, but some details like error checking, etc.. are omitted):
#!/usr/bin/env perl
package File::Persistent;
use strict;
use warnings;
use File::Slurp;
sub new {
my ($class, $opt) = @_;
$opt ||= {};
my $filename = $opt->{filename} || "./tmpfile";
my $self = {
_filename => $filename,
_content => "",
};
# Read in existing content
if (-s $filename) {
$self->{_content} = File::Slurp::read_file($filename);
}
bless $self, $class;
}
sub filename {
my ($self) = @_;
return $self->{_filename};
}
sub write {
my ($self, @lines) = @_;
$self->{_content} .= join("\n", @lines);
return;
}
sub DESTROY {
my ($self) = @_;
open my $file_handle, '>', $self->filename
or die "Couldn't save persistent storage: $!";
print $file_handle $self->{_content};
close $file_handle;
}
# Your script starts here...
package main;
my $file = File::Persistent->new();
$file->write("Some content\n");
# Time passes...
$file->write("Something else\n");
# Time passes...
$file->write("I should be done now\n");
# File will be written to only here..
I think you're looking for END
block:
END {
# cleanup
}
An END code block is executed as late as possible, that is, after perl has finished running the program and just before the interpreter is being exited, even if it is exiting as a result of a die() function. (But not if it's morphing into another program via exec, or being blown out of the water by a signal--you have to trap that yourself (if you can).) You may have multiple END blocks within a file--they will execute in reverse order of definition; that is: last in, first out (LIFO). END blocks are not executed when you run perl with the -c switch, or if compilation fails.