Reading a directory into an array using <>

Bignut_Squirrel has asked for the wisdom of the Perl Monks concerning the following question:

Monks,

My script needs to read all the files in a directory into an array for comparison. This works when I directly provide the path to the directory as below:

@filearray = </var/log/*>;
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I want to make the code more flexible so I need to store the directory in a variable instead, but this way does not seem to work:

$path = '/var/log/*';
@filearray = <$path>;
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This results in an empty array. I have tried different quotations, but I can't figure out the syntax. Is there a way to do this?

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Re: Reading a directory into an array using <> by toolic (Bishop) on Jun 16, 2011 at 19:55 UTC
If you use warnings, you should get a warning message like: `readline() on unopened filehandle at ...` [download] Also, if you use diagnostics, you should get a little more help on that message: `readline() on unopened filehandle at ... (#1) (W unopened) An I/O operation was attempted on a filehandle that w +as never initialized. You need to do an open(), a sysopen(), or a so +cket() call, or call a constructor from the FileHandle package.` [download] Well, those might not be the most helpful messages to you, but at least they give you an idea that something is amiss. To avoid the voodoo of <>, use glob: `use warnings; use strict; my $path = '/var/log/*'; my @files = grep { -f } glob $path;` [download] See also: use strict and warnings Basic debugging checklist	[reply] [d/l] [select]
Re: Reading a directory into an array using <> by Marshall (Canon) on Jun 16, 2011 at 19:45 UTC
to say get only the directories in my temp directory, you can use the glob() function: `#!/usr/bin/perl -w use strict; my $path = 'C:/temp/'; my @filearray = grep{-d}glob("$path*"); print join("\n",@filearray);` [download]	[reply] [d/l]
Re: Reading a directory into an array using <> by 7stud (Deacon) on Jun 16, 2011 at 20:30 UTC
If the string(sic --> should be 'thing') inside the angle brackets is anything other than a filehandle name or a scalar variable (even if there are just extra spaces), it is interpreted as a filename pattern to be 'globbed'. (Programmig Perl, p. 83) You have a scalar variable inside the angle brackets, so it is not interpreted as a filename pattern to be globbed. You could trick perl like this: `my @fnames = <${path}>` But since the angle operator calls glob() implicitly when you don't provide it with a file handle or scalar variable inside the brackets, you might as well just call glob() explicitly yourself. Note that the argument to glob() is a string, so you need quotes. You can also use opendir() and readdir(): `use strict; use warnings; use 5.010; my $path = '/var/log'; opendir(my $TARGET_DIR, $path) or die "Couldn't open directory $path: $!"; my @all_files = readdir $TARGET_DIR; closedir $TARGET_DIR;` [download] There are a couple of differences, though: 1) glob() will ignore invisible files, 2) glob() tacks the file name onto the specified path, where readdir() just returns the filenames.	[reply] [d/l] [select]