deleting all the files in a directory

[laredotornado]

Hello,

Using PHP 4, what are the shortest amount of lines I can write to
delete all the files in a given directory?

Thanks for your help, - Dave

[NC]

[e-mail] wrote:

Using PHP 4, what are the shortest amount of lines I can write to
delete all the files in a given directory?

One, if you are willing to live with an OS-dependent solution. You can
read your OS manual for the command that removes files (rm on Unix or
del on Windows), figure out what comand-line keys are necessary to
remove all files in a given directory, and pass the respective command
to your operating system via exec(), passthru(), or system().

Cheers,
NC

[Ewoud Dronkert]

la***********@zipmail.com wrote:

Using PHP 4, what are the shortest amount of lines I can write to
delete all the files in a given directory?

<?php $ret = `cd $mydir && rm -fr *`; ?>

--
E. Dronkert

[Andy Hassall]

On 13 Feb 2006 12:14:40 -0800, la***********@zipmail.com wrote:

Using PHP 4, what are the shortest amount of lines I can write to
delete all the files in a given directory?

$dir = '/x/y/z';
if ($dir = opendir($dir))
{
while (($file = readdir($dir)) !== false)
{
if (is_file("$dir/$file"))
{
unlink("$dir/$file");
}
}
}

If you really want it shorter you can remove some of the braces.

--
Andy Hassall :: an**@andyh.co.uk :: http://www.andyh.co.uk
http://www.andyhsoftware.co.uk/space :: disk and FTP usage analysis tool

[Ewoud Dronkert]

Andy Hassall wrote:

if (is_file("$dir/$file"))

You're potentially missing (symbolic) links and files larger than
int-size. Better to check for '.' or '..' filenames. Clumsy, I know.

--
E. Dronkert

[Iván Sánchez Ortega]

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Ewoud Dronkert wrote:

<?php $ret = `cd $mydir && rm -fr *`; ?>

I can halve that:

<?`rm -rf $mydir/*`;?>

- --
- ----------------------------------
Iván Sánchez Ortega -i-punto-sanchez--arroba-mirame-punto-net

http://acm.asoc.fi.upm.es/~mr/
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[Andy Hassall]

On Mon, 13 Feb 2006 22:47:26 +0100, Ewoud Dronkert
<fi*******@lastname.net.invalid> wrote:

Andy Hassall wrote:

if (is_file("$dir/$file"))
You're potentially missing (symbolic) links

Missing, or including? symlinks to files return true from is_file() if their
target is a file, so yes, that should probably have a && !is_link() condition
as well, depending on what the OP really wants deleted.
and files larger than int-size.

Hm, didn't know about that one. http://bugs.php.net/bug.php?id=27792

--
Andy Hassall :: an**@andyh.co.uk :: http://www.andyh.co.uk
http://www.andyhsoftware.co.uk/space :: disk and FTP usage analysis tool

[Ewoud Dronkert]

Andy Hassall wrote:

Missing, or including? symlinks to files return true from is_file() if their
target is a file, so yes, that should probably have a && !is_link() condition
as well, depending on what the OP really wants deleted.

My guess is, not that but || is_link().

--
E. Dronkert

[Jim Michaels]

"Andy Hassall" <an**@andyh.co.uk> wrote in message
news:6h********************************@4ax.com...

On 13 Feb 2006 12:14:40 -0800, la***********@zipmail.com wrote:

Using PHP 4, what are the shortest amount of lines I can write to
delete all the files in a given directory?

this works for one directory, but not subdirectories under it. for that, it
needs to be recursive.

function zapdir($dir) {
if ($dir = opendir($dir)) {
while (($file = readdir($dir)) !== false) {
if (is_file("$dir/$file")) {
unlink("$dir/$file");
}
//is a directory or a symlink
if (is_dir("$dir/$file") && "." != $file && ".." != $file) {
zapdir("$dir/$file");
rmdir("$dir/$file") or echo "unable to remove directory
$dir/$file\n";
}
if (is_link("$dir/$file")) {
unlink("$dir/$file"); //remove symbolic link. does not
remove original file AFAIK
}
}
}
}
zapdir('/x/y/z');

If you really want it shorter you can remove some of the braces.
--
Andy Hassall :: an**@andyh.co.uk :: http://www.andyh.co.uk
http://www.andyhsoftware.co.uk/space :: disk and FTP usage analysis tool

[d]

"Jim Michaels" <jm******@nospam.yahoo.com> wrote in message
news:kZ********************@comcast.com...

"Andy Hassall" <an**@andyh.co.uk> wrote in message
news:6h********************************@4ax.com...

On 13 Feb 2006 12:14:40 -0800, la***********@zipmail.com wrote:

Using PHP 4, what are the shortest amount of lines I can write to
delete all the files in a given directory?

this works for one directory, but not subdirectories under it. for that,
it needs to be recursive.

function zapdir($dir) {
if ($dir = opendir($dir)) {
while (($file = readdir($dir)) !== false) {
if (is_file("$dir/$file")) {
unlink("$dir/$file");
}
//is a directory or a symlink
if (is_dir("$dir/$file") && "." != $file && ".." != $file) {
zapdir("$dir/$file");
rmdir("$dir/$file") or echo "unable to remove directory
$dir/$file\n";
}
if (is_link("$dir/$file")) {
unlink("$dir/$file"); //remove symbolic link. does not
remove original file AFAIK
}
}
}
}
zapdir('/x/y/z');

That will run out of stack space in large directory trees... Best to close
the $dir before calling zapdir...
If you really want it shorter you can remove some of the braces.

--
Andy Hassall :: an**@andyh.co.uk :: http://www.andyh.co.uk
http://www.andyhsoftware.co.uk/space :: disk and FTP usage analysis tool

[Mladen Gogala]

On Mon, 13 Feb 2006 22:47:26 +0100, Ewoud Dronkert wrote:

You're potentially missing (symbolic) links and files larger than
int-size. Better to check for '.' or '..' filenames. Clumsy, I know.

This will work better:

foreach (glob("/mydir/*") as $f) {
filetype($f)== 'file' ? unlink($f) : null;
}

If my coding style betrays using some other scripting languages
as well, I cannot help it. In some other scripting languages that
might have been coded like this:

foreach (glob "/mydir/*") {
unlink($_) if -f $_;
}

As I don't have "suffix if" in PHP, I came up with the ternary operator.
Note that I could have written '' instead of "null" and still have the
same effect. Of course, I cannot rewrite something like this:

map { unlink($_) if -f $_; } glob("/mydir/*");

--
http://www.mgogala.com

[Mladen Gogala]

On Mon, 13 Feb 2006 21:34:28 +0100, Ewoud Dronkert wrote:

<?php $ret = `cd $mydir && rm -fr *`; ?>

That will be a little harder on a Windows system.

--
http://www.mgogala.com

[Mladen Gogala]

On Mon, 13 Feb 2006 21:14:36 +0000, Andy Hassall wrote:

if ($dir = opendir($dir))
{
while (($file = readdir($dir)) !== false)

PHP supports globs, just as Perl does.

--
http://www.mgogala.com

[Ewoud Dronkert]

Mladen Gogala wrote:

PHP supports globs, just as Perl does.

Yeah, I'm always forgetting. Thanks.

--
E. Dronkert

[Bart the bear]

Mladen Gogala wrote:

map { unlink($_) if -f $_; } glob("/mydir/*");

Speaking of this, is there any chance of references to functions in
PHP?
The "{ unlink($_) if -f $_; }" part of the code here is so called
"anonymous
subroutine" or "subroutine reference" which is sort of convenient if
you don't
want to clutter the namespace with unneeded function names. All you
need
to be able to implement your one-liner in PHP is an anonymous function
reference
to pass to array_walk, which is identical to Perl's "map".
Also, Perl has qr() construct which compiles regular expressions and
makes
things significantly faster. Is there any flag to compile regular
expression in
prreg_match? The only documented flag here is to capture offset. If I
need to
go through multiple lines in a loop, will PHP compile the regular
expression?
The situation I have in mind is something like this:

while ( $line=fread($file,128)) {
if preg_match("/$regexp/",$line,$found)....
}

As you can see, I'm a beginner with PHP. I have 5 years or so
experience
with Perl.

[Andy Hassall]

On 15 Feb 2006 12:23:33 -0800, "Bart the bear" <ba*********@gmail.com> wrote:

Speaking of this, is there any chance of references to functions in
PHP?
The closest is create_function() which isn't as good as Perl's ability to pass
code blocks, as you have to embed the anonymous function source in a string.

http://uk2.php.net/create_function
Also, Perl has qr() construct which compiles regular expressions and
makes
things significantly faster. Is there any flag to compile regular
expression in
prreg_match?

Looking at the PHP source code, at least for PHP 5.1.2, it already compiles
expressions on first use and keeps the results in a cache - subsequent calls
use the cached compiled version. At least from a quick inspection of
ext/pcre/php_pcre.c, e.g. line 438, within php_pcre_match:

/* Compile regex or get it from cache. */
if ((re = pcre_get_compiled_regex(regex, &extra, &preg_options
TSRMLS_CC)) == NULL) {
RETURN_FALSE;
}

--
Andy Hassall :: an**@andyh.co.uk :: http://www.andyh.co.uk
http://www.andyhsoftware.co.uk/space :: disk and FTP usage analysis tool

[Iván Sánchez Ortega]

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Mladen Gogala wrote:

On Mon, 13 Feb 2006 21:34:28 +0100, Ewoud Dronkert wrote:

<?php $ret = `cd $mydir && rm -fr *`; ?>

That will be a little harder on a Windows system.

Do you mean that <?php `rmdir /s $mydir`;?> is harder than that?

;-)

- --
- ----------------------------------
Iván Sánchez Ortega -i-punto-sanchez--arroba-mirame-punto-net

http://acm.asoc.fi.upm.es/~mr/
Proudly running Debian Linux with 2.6.12-1-686 kernel, KDE3.5.0, and PHP
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[Iván Sánchez Ortega]

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Bart the bear wrote:

Speaking of this, is there any chance of references to functions in
PHP?

Aside from lambda-style functions (see create_function()), you can reference
a function by its name:

<?php

function foo()
{
echo "wow!";
}

$bar = 'foo';

$bar();

?>
- --
- ----------------------------------
Iván Sánchez Ortega -i-punto-sanchez--arroba-mirame-punto-net

No intentes doblar la cuchara, eso es imposible; simplemente intenta
comprender la verdad: que no hay cuchara
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[Mladen Gogala]

On Wed, 15 Feb 2006 21:18:58 +0000, Andy Hassall wrote:

The closest is create_function() which isn't as good as Perl's ability to pass
code blocks, as you have to embed the anonymous function source in a string.
Yes, but it is still much more cumbersome then Perl mechanism of
references. Quite frankly, the only thing that references are really
needed for is to model self-referential structures like doubly linked
lists and alike. Personally, I find "foreach" version much more
understandable then "map" version. Speaking of Perl, I have my
own personal style of coding. My former boss, now my friend finds
Perl idioms like:

$a ||= "default";

repugnant and disgusting. He will always write the same thing
like this:

if (!defined($a)) {
$a="default";
}

PHP doesn't allow the 1st form and that is a good thing because the
||= version is the best way to write an obfuscated code which will be
misunderstood by the maintainer coming after the author. One frequent
version of the code above is

bless $var1 ref($_[0])||$_[0];

which is something that will scare away anybody who dreams of
learning Perl. I believe that not being able to write things
as concisely as in Perl is not necessarily a bad thing. Emulating
obfuscating loops by "map" function and an anonymous references
is not something that should be hastily implemented. If you want
to learn PHP, it is an order of magnitude easier to learn then
Perl.

Here I am running a risk to turn this thread into a religious war
between PHP and Perl fans. That is not my intention, I use both as,
I believe, you do as well. Both languages have their strengths and
weaknesses. I find them well complementing each other. Perl has
a PHP module, containing many of the much coveted PHP functions,
while PHP has PECL Perl module which makes it possible to run
Perl scripts from PHP. No need for religious war from either side.

http://uk2.php.net/create_function

Also, Perl has qr() construct which compiles regular expressions and
makes
things significantly faster. Is there any flag to compile regular
expression in
prreg_match?

Looking at the PHP source code, at least for PHP 5.1.2, it already compiles
expressions on first use and keeps the results in a cache - subsequent calls
use the cached compiled version. At least from a quick inspection of
ext/pcre/php_pcre.c, e.g. line 438, within php_pcre_match:

/* Compile regex or get it from cache. */
if ((re = pcre_get_compiled_regex(regex, &extra, &preg_options
TSRMLS_CC)) == NULL) {
RETURN_FALSE;
}

This I didn't know. Thanks for the info.
--
http://www.mgogala.com

[Jasen Betts]

On 2006-02-15, Mladen Gogala <go****@sbcglobal.net> wrote:

On Mon, 13 Feb 2006 21:34:28 +0100, Ewoud Dronkert wrote:

<?php $ret = `cd $mydir && rm -fr *`; ?>

That will be a little harder on a Windows system.

not really.

<?php $ret=`deltree $mydir\\*.*` ; ?>

--

Bye.
Jasen