use strict;
use warnings;

my $filename = 'myinfo.txt';

# Create the test file
open my $outFile, '>', $filename or die "Failed to create $filename: $!";
print $outFile <<FILE;
Program name: some junk
Author: dude
Company: no name
Phone: 123.345.1234
Version: 1.0
FILE
close $outFile;

# 'Edit' the file
local @ARGV = $filename;
local $^I = '.bak';

while (<>) {
    next if /^Phone:/;
    
    s/^Author:.*/Author: Johny5/;
    print;
}

##</code><code>##

Program name: some junk
Author: Johny5
Company: no name
Version: 1.0