Sorting filenames

[dh87lfc]

Hi,
I started using Perl a few days ago on Linux and have a bit of a problem. I have created a code which reads the content of every file in a directory, which works, but reads them in the wrong order. I have been searching for a function which reads the files in numerical order according to the filename (the letters in each filename are the same but the numbers increase by one each time). This is the code:

#!/usr/bin/perl
opendir (DH, "directory");
while ($file = readdir(DH))
{
    open (FH, $file);
    while(<FH>)
    {
        chomp;
        print "$_\n";
    }
}
close (FH);
 

Any help would be appreciated, thanks in advance.

[numberwhun]

Hi,
I started using Perl a few days ago on Linux and have a bit of a problem. I have created a code which reads the content of every file in a directory, which works, but reads them in the wrong order. I have been searching for a function which reads the files in numerical order according to the filename (the letters in each filename are the same but the numbers increase by one each time). This is the code:

#!/usr/bin/perl
opendir (DH, "directory");
while ($file = readdir(DH))
{
    open (FH, $file);
    while(<FH>)
    {
        chomp;
        print "$_\n";
    }
}
close (FH);
 

Any help would be appreciated, thanks in advance.

Well, one thing you could do, per the readdir page, is to read the directory listing with readdir into a list (array). That way it puts the entire listing into an array. Once it is in the array you can use the sort function to sort it, then read it one element at a time.

Also, when using readdir, it is customary and proper to use closedir() when you are done. It isn't required, but it is good coding practice.

Regards,

Jeff

[KevinADC]

but reads them in the wrong order

It is reading them in the order the system has them stored in. That is rarely any type of logically sorted order to humans. If you use an application to see the files on your computer ( a file manager application ) that application generally defaults to sorting files by name which is easiest for humans to find things.

When you use perl to read the files in a directory you have to write your own sorting function.

[dh87lfc]

Hi,
thanks for the help. I put the filenames into an array and used the sort function and it worked.