How can I open and edit files through Perl? - file

Question

I want to give the user input (multi-line) and print the multi-line output to a new file named by the user with
I've already tried
say "enter filename";
chomp(my $filename = <STDIN>);
open my $fn, '>', $filename;
say "enter contents";
print "> ";
chomp(my $contents = <STDIN>);
print {$fn} $contents;
close $fn;
but that only works with one line.
say "enter filename";
chomp(my $filename = <STDIN>);
open my $fn, '>', $filename;
say "enter contents";
print "> ";
chomp(my $contents = <STDIN>);
print {$fn} $contents;
close $fn;
but multi-line and creates a new file, not edits an old one
It either doesn't create a file, doesn't edit a file, or just doesn't do anything at all.

Answer 1

To type out a new file or add lines to an existing one
use warnings;
use strict;
use feature 'say';
my $filename = shift; # Better use a module (eg. Getopt::Long)
if (not $filename) {
$filename = get_filename();
}
elsif (-f $filename) {
say "Appending to file \"$filename\".";
}
elsif (-e $filename and not -f $filename) {
say "The \"$filename\" exists but is not a plain file.";
$filename = get_filename();
}
else {
say "Creating file \"$filename\"";
}
open my $fh, '>>', $filename or die "Can't open $filename: $!";
say "\nEnter lines to add. Press Ctrl-D when done.\n";
print "> ";
while (my $line = <STDIN>) {
print $fh $line;
print "> ";
}
sub get_filename {
print "Enter the name for a file to create/edit: ";
chomp (my $filename = <STDIN>);
while (-e $filename and not -f $filename) {
say "The \"$filename\" exists but is not a plain file.";
print "Enter the name for a file to create/edit: ";
chomp ($filename = <STDIN>);
}
usage() if not $filename;
return $filename;
}
sub usage {
say STDERR "Usage: $0 [filename]";
exit;
}
Note that the actual writing of user's input can be written simply as
print $fh $_ while <STDIN>;
All the rest is management of user input, checking etc. That can be organized in many ways, depending on details of possible uses. The above is a simple take, please change and tweak as suitable.

Answer 2

Here is an example that lets you exit the loop by pressing CTRL-C:
use feature qw(say);
use strict;
use warnings;
STDOUT->autoflush(1);
say "enter filename";
chomp(my $filename = <STDIN>);
open my $fh, '>', $filename or die "Could not open file '$filename': $!";
{
local $SIG{INT} = sub { die "SIGINT" };
say "enter contents (CTRL-C to exit)";
eval {
while (1) {
print "> ";
my $contents = <STDIN>; # do not need chomp here
print $fh $contents;
}
};
close $fh;
say "\nDone. Saved file '$filename'";
}