in reply to Re: FTP and update files from a list
in thread FTP and update files from a list

It feels like homework, but it's work work.

Anyway, I figured I would open the list of files and read them into an array. And please don't laugh, but I really am new to this language! I'm sure I'm missing some subtleties in what follows:

open FILE_LIST, "list.txt";
while(<FILE_LIST>) {
 #read each line into the array here -- gotta look up the syntax
}
close FILE_LIST;

[download]

Then, I figured I'd iterate through the array and FTP the files to the working directory, which I don't yet know how to do.

Next, I'd save off the .bak copies, doing something like this:

foreach $filename (@files2change) {
 my $backup = $filename . '.bak';
 rename($filename, $backup)
 open OLD_FILE, $backup;
 open NEW_FILE, ">>$filename;
 while(<OLD_FILE>) {
  print NEW_FILE s/foo/bar/g;
 }
 close OLD_FILE;
 close NEW_FILE;
}

[download]

And finally, FTP the updated files back.

Replies are listed 'Best First'.
Re^3: FTP and update files from a list
by Scrat (Monk) on Mar 28, 2006 at 05:39 UTC
    Here's a quick example how you can use ftp to transfer your updated txt files: 
    use strict;
use warnings;

use Net::FTP;

my ($ftp);
my $host      = "xxx.xxx.xxx.xxx";
my $directory = "destination";
my $localDir  = "C:\textfiles";

print "Connecting to $host ...";
if ($ftp=Net::FTP->new($host,Timeout=>240))
{
    print "Successful\n";
    print "Logging in ...";
    if ($ftp->login("username","password"))
    {
        print "Successful\n";
        print "Changing Directory to $directory ...";
        if ($ftp->cwd($directory))
        {
            print "Successful\n";
            print "Transfering Files\n";
            &FileSend($localDir);
            $ftp->quit;
        }
        else
        {
            print "Failed\n";
        }
    }
    else
    {
        print "Failed\n";
    }
}
else
{
    print "Failed\n";
}
##################################################
# Sub Routines                            
##################################################
sub FileSend()
{
    my $dir = shift;
    if (opendir DIR, $dir)
    {
        while (my $file = readdir DIR) 
        {    
            #print "$file\n";
            if ($file =~ /txt$/)  #finds plain text files
            {
                print "Sending htm files $file ... ";
                if ($ftp->put($file))
                 {
                     print "Successful\n";
                     #unlink ($file);  # delete file after ftp
                }
                else
                {
                    print "Failed\n";
                }
            }
            else 
            {
                next;
            }
        }
    }
    else
    {
        print "Error opening handle\n";
    }
}

    [download]
    Cheers

    Scrat
[reply]
[d/l]
Re^3: FTP and update files from a list
by graff (Chancellor) on Mar 28, 2006 at 11:39 UTC
    Well, this line is really wrong: 
       print NEW_FILE s/foo/bar/g;

    [download]
    The "s///" operator will return true or false (1 or 0), and that is what the "print" function will get. Your output file will have a "0" or a "1" for each line of the input file, instead of the actual data.

    Also, you're likely to run this script more than once (since you probably won't get everything right the first time), so you probably want the edited versions of files to be in a different directory (keep the source files and source directory unchanged), and you surely don't want to open the output files with  ">>$filename".

    Since perl gets used for this sort of thing a lot, there are a lot of short-cuts to make it easier. You could do the edit like this: 

    #!/usr/bin/perl

use strict;

# suppose original files are in directory "source", and
# we want to put edited versions into directory "edited":

my @files = <source/*>;  # that's called a "file glob"

for my $ifile ( @files ) {
    my $ofile = $ifile;
    $ofile =~ s/source/edited/;
    open( I, "<", $ifile );
    open( O, ">", $ofile ) or die "$ofile: $!";
    while (<I>) {
        s/foo/bar/g;
        print O;
    }
    close I;
    close O;
}

    [download]
    As for the FTP part, if the remote machine is running an anonymous-ftp server, and the files in question are available that way, then Net::FTP is fine. But if you need to use a particular (non-anonymous) user account and a password, you really should use Net::SFTP.

    I would recommand that you keep the (S)FTP stuff in a separate script from the editing stuff. (It's actually more likely that you don't need a perl script at all to do the file transfers between machines, but if you want to make up a perl script to "reinvent" the existing (s)ftp programs, go ahead.)

    The point is that you can write a re-usable file-transfer script that will be handy for lots of occasions (assuming the standard tools are less handy), and you can even write a re-usable editing script for making changes to a list of files, which will be handy for lots of occasions (it is possible to provide a list of regex substitutions as an input). Both of these things are relatively easy.

    But if a script is going to do both file transfers and editing, that one script will be larger and more complicated and will take longer to write; and making it re-usable in any practical sense is going to be a lot more difficult.

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