(PHP 4, PHP 5, PHP 7)
rename — 重命名一个文件或目录
$oldname
, string $newname
[, resource $context
] )
尝试把 oldname 重命名为
newname。
oldname
Note:
用于
oldname中的封装协议必须和用于newname中的相匹配。
newname新的名字。
contextNote: 在 PHP 5.0.0 中增加了对上下文（Context）的支持。有关上下文（Context）的说明参见 Streams。
成功时返回 TRUE， 或者在失败时返回 FALSE。
| 版本 | 说明 |
|---|---|
| 5.3.1 | 可以在 Windows 上跨驱动器 rename() 文件。 |
| 5.0.0 | rename() 也可用于某些 URL 封装协议。参见支持的协议和封装协议 的列表看看 rename() 支持哪些 URL 封装协议。 |
| 4.3.3 | 在有适当权限的时候 rename() 已经能够在基于 *nix 的系统中跨磁盘分区重命名文件。Warnings may be generated if the destination filesystem doesn't permit chown() or chmod() system calls to be made on files — for example, if the destination filesystem is a FAT filesystem. |
Example #1 rename() 例子
<?php
rename("/tmp/tmp_file.txt", "/home/user/login/docs/my_file.txt");
?>
If $oldname and $newname are existing hard links referring to the same file, then rename() does nothing, and returns a success status.
(from the underlying libc rename() manual)
On the other hand "/bin/mv oldname newname" results in the removal of "oldname".
If $source is a valid folder, what do you think this does:
<?php
rename($source, '@');
?>
In 99% of the time you will get a warning, and $source remains untouched.
However, if you're working on Windows, and on a mapped network drive occasionally $source will be moved to folder '@' which will be located at PHP's working directory.
How about this:
<?php
rename($source, $source . '\folder1');
?>
This makes $source inaccessible.
Of course, it's stupid to move $source into a sub-folder like that. I'd expect an error. Yet, no error or warning. And the script "freezes".
I had few instances where rename simply deleted files & folders. I have not been able figure out why.
In a nut shell, be-careful when using rename.
From the Changelog notes:
"Warnings may be generated if the destination filesystem doesn't permit chown() or chmod() system calls to be made on files — for example, if the destination filesystem is a FAT filesystem."
More explicitly, rename() may still return (bool) true, despite the warnings that result from the underlying calls to chown() or chmod(). This behavior can be misleading absent a deeper understanding of the underlying mechanics. To rename across filesystems, PHP "fakes it" by calling copy(), unlink(), chown(), and chmod() (not necessarily in that order). See PHP bug #50676 for more information.
On UNIX-like operating systems, filesystems may be mounted with an explicit uid and/or gid (for example, with mount options "uid=someuser,gid=somegroup"). Attempting to call rename() with such a destination filesystem will cause an "Operation not permitted" warning, even though the file is indeed renamed and rename() returns (bool) true.
This is not a bug. Either handle the warning as is appropriate to your use-case, or call copy() and then unlink(), which will avoid the doomed calls to chown() and chmod(), thereby eliminating the warning.
[Editor note: this works because SplFileObject has the __toString() method which returns the file path]
Note that you can pass an SplFileInfo object as either argument:
<?php
# Assume a file 'foo' in the current directory
rename('foo', new SplFileInfo('bar'));
# foo is now bar!
rename(new SplFileInfo('bar'), 'foo');
# bar is now foo again
?>
> rename() may now be able to rename files across partitions on *nix based systems
seems it's not true, because
PHP Fatal error: Uncaught exception 'Exception' with message 'rename(/tmp/tables_new/#translit.csv,/home/crmdev/www/bpl-syrena/tables_new/#translit.csv): Operation not permitted'
> rename() may now be able to rename files across partitions on *nix based systems
Seems it's not true.
PHP Fatal error: Uncaught exception 'Exception' with message 'rename(/tmp/tables_new/#translit.csv,/home/crmdev/www/bpl-syrena/tables_new/#translit.csv): Operation not permitted'
$ mount
/dev/mapper/fedora00-root on / type ext4 (rw,relatime,seclabel,data=ordered)
tmpfs on /tmp type tmpfs (rw,seclabel)
If you use SplFileObject for the same file which
you want to rename you have to remove SplFileObject objec first.
<?php
$filePath = 'testFile.txt';
$fileObj = new SplFileObject( $filePath );
rename( $filePath, 'newName.txt' );
// You will get - Permission denied error
$filePath = 'testFile.txt';
$fileObj = new SplFileObject( 'filePath.txt' );
$fileObj = null;
rename( $filePath, 'newName.txt' );
// and now it is working.
?>
For those encountering the error:
No error in "path/to/script/file" at line XX
Check that the new filename (or both for safety) do not contain characters forbidden by the system.
For example, forbidden characters in filenames on Windows:
http://msdn.microsoft.com/en-us/library/windows/desktop/aa365247(v=vs.85).aspx
Hope this helps!
Important note - rename() does NOT work for *directories* across filesystems or devices. Only *files*
You will get two warnings:
"PHP Warning: rename(): The first argument to copy() function cannot be a directory in <whatever> on line <whatever>"
"PHP Warning: rename(t2,/var/run/test/t2): Invalid cross-device link in <whatever> on line <whatever>"
The copy() mentioned I assume is C's copy() and not PHP's copy() function. There is an associated bug in the Ubuntu bug system for this as well, that was escalated to bugs.php.net:
https://bugs.php.net/bug.php?id=54097
The only workarounds right now I believe is using PHP copy($source, $dest) and then on success, PHP unlink($source), or doing system("mv $source $dest") which is hokey, and should be surrounded by quotes for paths with spaces or other shell metacharacters, and possibly escaped for security.
Interesting to note that if you are trying to rename a file within a folder adding a slash in front of the folder (even if the folder is in the root of your server) will not work.
in other words, if you have the folder "tmp" in your server's root:
<?php
rename("/tmp/tmp_file.txt", "/tmp/my_file.txt"); // will not work
rename("tmp/tmp_file.txt", "tmp/my_file.txt"); // WILL work!
?>
on windows (XP, vista, 7...) http://fr.wikipedia.org/wiki/Windows-1252", if your file name contains accent, it doesn't work basically. So use iconv function to convert from utf-8 to cp1252 as bellow :
<?php
$nomfichierinitial=iconv("UTF-8", "CP1252", "C:\\wamp\\www\\tést.txt");
$nomfichierfinal="C:\\wamp\\www\\test.txt";
rename($nomfichierinitial, $nomfichierfinal);
?>
I could not get this to work at first, then saw that I was using a site url constant ahead of my target folder/filename. After re-reading the example I changed my constant to a filesystem type, like <?php rename( old_filename.ext, $_SERVER['DOCUMENT_ROOT']"/target/folder/my_new_filename.ext"); ?> and it worked like a charm.
a simpler code for changing file extentions of multiple files in your working directory.
#!/usr/bin/php
<?php
//What? Quick CLI-tool to rename the file extensions of multiple files (in working directory) matching the pattern.
//Author? ZuZi
//Date? 2013/02/14
if($argv[1] && $argv[2]){
foreach (glob("*.$argv[1]") as $filename) {
echo ("change $filename to ".substr($filename,0,-(strlen($argv[1])))."$argv[2]\n");
rename("$filename", substr($filename,0,-(strlen($argv[1])))."$argv[2]");
}
}else
exit("\nERROR: ARGUMENTS MISSING!\n\nChanges the extension of all files matching <source> to <target>, in working directory.\n
usage: changeFileType source target \n\n");
?>
rename() is working on Linux/UNIX but not working on Windows on a directory containing a file formerly opened within the same script. The problem persists even after properly closing the file and flushing the buffer.
<?php
$fp = fopen ("./dir/ex.txt" , "r+");
$text = fread($fp, filesize("../dir/ex.txt"));
ftruncate($fp, 0);
$text2 = "some value";
fwrite ($fp, $text2 );
fflush($fp);
fclose ($fp);
if (is_resource($fp))
fclose($fp);
rename ("./dir", ".dir2"); // will give a ?permission denied? error
?>
Strangely it seem that the rename command is executed BEFORE the handle closing on Windows.
Inserting a sleep() command before the renaming cures the problem.
<?php
$fp = fopen ("./dir/ex.txt" , "r+");
$text = fread($fp, filesize("../dir/ex.txt"));
ftruncate($fp, 0);
$text2 = "some value";
fwrite ($fp, $text2 );
fflush($fp);
fclose ($fp);
if (is_resource($fp))
fclose($fp);
sleep(1); // this does the trick
rename ("./dir", ".dir2"); //no error
?>
Code first, then explanation.
<?php
rename ("/folder/file.ext", "newfile.ext");
?>
That doesn't rename the file within the folder, as you might assume, instead, it moves the file to whatever the PHP working directory is... Chances are you'll not find it in your FTP tree. Instead, use the following:
<?php
rename ("/folder/file.ext", "/folder/newfile.ext");
?>
This code renames all files and folders in a specific directory to lower case:
<?php
$path = "my_doc";
function getDirectory( $path = '.', $level = 0 ){
$ignore = array( 'cgi-bin', '.', '..' );
$dh = @opendir( $path );
while( false !== ( $file = readdir( $dh ) ) )
{
if( !in_array( $file, $ignore ) )
{
$spaces = str_repeat( ' ', ( $level * 4 ) );
if( is_dir( "$path/$file" ) )
{
echo "<strong>$spaces $file</strong><br />";
rename($path."\\".$file, strtolower($path."\\".$file));
getDirectory( "$path/$file", ($level+1) );
}
else {
echo "$spaces $file<br />";
rename($path."\\".$file, strtolower($path."\\".$file));
}
}
}
closedir( $dh );
}
getDirectory( $path , 0 )
?>
For those who are still confused about the behavior of rename() in Linux and Windows (Windows XP) when target destination exists:
I have tested rename($oldName, $targetName) in PHP 5.3.0 and PHP 5.2.9 on both OS and find that if a file named $targetName does exist before, it will be overwritten with the content of $oldName
In Windows, on FAT32, rename will fail with "bad file descriptor" if the underlying short (8.3) file name of the file to rename is the same as the new file name. For example, attempting to rename "Oxygène.m3u" to "Oxygene.m3u" will fail if the 8.3 name of "Oxygène.m3u" is "OXYGENE.M3U" (which is very likely), as Windows will take both names as belonging to the same file. To solve this you must first rename the file to an intermediate name and then rename it to the intended name. To see the short (8.3) file names in a directory you can type DIR /X on a cmd box.
Note that this WILL NOT WORK if trying to rename a directory to a network share.
e.g.
rename('/home/user/me/dir1', '/mnt/shares/nfsmount/dir2')
will create a file called 'dir2' on the share and not a directory.
This caught me out and my (quickest) solution was to use an exec and mv command:
<?php
$cmd = 'mv "/home/user/me/dir1" "/mnt/shares/nfsmount/dir2"';
exec($cmd, $output, $return_val);
if ($return_val == 0) {
echo "success";
} else {
echo "failed";
}
?>
This is an update to the code provided by dev at islam-soft dot com, which renames all files in a directory with a given extension to have a different extension.
I updated four things: Most important, added a check to make sure the extension matched ONLY the end of the filename (the original caused me a number of headaches when it started matching things in the middle of filenames instead of at the end where a proper extension belongs), 2nd added some feedback about what is going on, if you choose verbose mode=TRUE, 3rd added the "testing" parameter so you can do a test run before committing for real, 4th added an error message if a rename fails.
parameter 1 : the directory name
parameter 2 : the first extension which we want to replace
parameter 3 : the new extension of files
parameter 4 : verbose? (true/false)
parameter 5 : testing? (true/false)--if true, won't actually rename anything; if you do verbose=TRUE and testing=TRUE you can see what will happen before committing to it with testing=FALSE.
Return is the number of files renamed.
for a simple usage call the function :
changeext('my/directory', 'html', 'php', false, false);
This changes every file name with extension html into php in the directory my/directory
<?PHP
//changes files in $directory with extension $ext1 to have extension $ext2
//note that if file.ext2 already exists it will simply be over-written
function changeext($directory, $ext1, $ext2, $verbose = false, $testing=true) {
if ($verbose && $testing) { echo "Testing only . . . <br />";}
$num = 0;
if($curdir = opendir($directory)) {
if ($verbose) echo "Opening $directory . . .<br />";
while($file = readdir($curdir)) {
if($file != '.' && $file != '..') {
$srcfile = $directory . '/' . $file;
$string = "$file";
$str = strlen($ext1);
$str++;
$newfile = substr($string, 0, -$str);
$newfile = $newfile.'.'.$ext2;
$dstfile = $directory . '/' . $newfile;
if (eregi("\.$ext1". '$' ,$file)) { # Look at only files with a pre-defined extension, '$' ensures the ext is only at they end of the filename
//I think the next two lines are unnecessary but they
//don't hurt anything so I'm leaving them
$fileHand = fopen($srcfile, 'r');
fclose($fileHand);
if (!$testing) {
$result=rename($srcfile, $dstfile );
if (!$result) echo "ERROR renaming $srcfile -> $dstfile<br />";
}
if ($verbose) echo "$srcfile -> $dstfile<br />";
}
if(is_dir($srcfile)) {
$num += changeext($srcfile, $ext1, $ext2, $verbose, $testing);
}
}
}
closedir($curdir);
}
return $num;
}
$testing=true;
$verbose=true;
//example usages, first run with $testing set to false, then change $testing to true to do them for real:
//changeext('your/directory', 'php', 'html', $verbose, $testing);
//changeext('your/directory', 'html', 'php', $verbose, $testing);
When I'm using unlink() or rename() with a SSH2.SFTP wrapper, both functions always return FALSE (but without a warning) even on success.
Example:
$connection = ssh2_connect(SERVER_NAME, PORT);
ssh2_auth_password($connection, USERNAME, PASSWORD);
$sftp = ssh2_sftp($connection);
unlink("ssh2.sftp://$sftp/" . REMOTE_DIRECTORY . FILENAME); // returns FALSE on success and on failure
rename("ssh2.sftp://$sftp/" . REMOTE_DIRECTORY . OLD_FILENAME, "ssh2.sftp://$sftp/" . REMOTE_DIRECTORY . NEW_FILENAME); // returns FALSE on success and on failure
If by any chance you end up with something equivalent to this:
<?php
rename('/foo/bar','/foo/bar');
?>
It returns true. It's not documented.
This might be a similar problem to what happened to:
jmalinsky at gmail dot com
10-Dec-2005 08:41
Apparently rename() will fail on filenames that are too large and emit an E_WARNING.
I was using rename() 'batch-move' a bunch of images. These files were lost in translation; in other words: deleted. One file, however, was moved but the filename was truncated. Weird. Why one or two files while the rest were deleted. This was being attempted on a Windows box.
I hope this helps anyone. If anyone has an explanation please feel free to email me. But if you're one of those idiots who *thinks* they're better than everyone and you *think* you know everything, don't bother.
Until recently you could end the dirname your wanted to rename to with a slash:
rename("mydir/my2nddir/","mydir/my3nddir/")
But now it doesn't work (php warns that it is unable to access mydir/my3nddir/).
So always leave out a final slash in your dirname:
rename("mydir/my2nddir","mydir/my3nddir")
The same goes for mkdir().
- rename extension of files
changeext($directory, $ext1, $ext2, $verbose)
i wrote this function to rename the extention of some files in a folder and sub-folders inside it ..
parameter 1 : the directory name
parameter 2 : the first extention wich we want to replace
parameter 3 : the new extention of files
for a simple usage call the function :
changeext('dir', 'html', 'php', 'false');
to change evry file name with extention html into php in the directory dir
<?php
function changeext($directory, $ext1, $ext2, $verbose = false) {
$num = 0;
if($curdir = opendir($directory)) {
while($file = readdir($curdir)) {
if($file != '.' && $file != '..') {
$srcfile = $directory . '/' . $file;
$string = "$file";
$str = strlen($ext1);
$str++;
$newfile = substr($string, 0, -$str);
$newfile = $newfile.'.'.$ext2;
$dstfile = $directory . '/' . $newfile;
if (eregi("\.$ext1",$file)) { # Look at only files with a pre-defined extension
$fileHand = fopen($srcfile, 'r');
fclose($fileHand);
rename($srcfile, $dstfile );
}
if(is_dir($srcfile)) {
$num += changeext($srcfile, $ext1, $ext2, $verbose);
}
}
}
closedir($curdir);
}
return $num;
}
changeext('dir', 'html', 'php', 'false');
?>
to remove the extention of files , just leave the parameter $ext2 blank ''
This was a fun one-- on Win XP, rename throws a "permission deined" if you try to rename across volumes.. i.e. rename("c:\windows\temp\x.txt", "g:\destination") will fail.
As of PHP 5.1.4 compiled on a mac, using rename with spaces one should just use the space. Take for example:
rename("/tmp/somefile.tar", "/mnt/laptop storage/somefile.tar");
If you use the backslash, like if you were cd-ing to the directory, rename will fail. Example:
rename("/tmp/somefile.tar", "/mnt/laptop\ storage/somefile.tar");
While not really a bug, it did confuse me for a little bit while working on a backup script.
As described from the unlink() page:
You have to release any handles to the file before you can rename it (True on Windows, at least).
This will NOT work, you'll receive permission denied errors:
<?php
$fileHand = fopen('tempFile.txt', 'r');
rename( 'tempFile.txt', 'tempFile2.txt' ); // Permission Denied!
?>
Simply close the handle to fix this:
<?php
$fileHand = fopen('tempFile.txt', 'r');
fclose($fileHand);
rename( 'tempFile.txt', 'tempFile2.txt' );
?>
This has me scratching my head for some time, as the handle was opened at the top of a marge function, and the rename was at the bottom.
I have programmed a really nice program that remotely lets you manage files as if you have direct access to them (http://sourceforge.net/projects/filemanage/). I have a bunch of really handy functions to do just about anything to files or directories. In it I just finished redevloping the directory move function to utilize PHP's rename() since it is way more efficient than a copy/delete process. It goes through (recursivly) and renames all the files to a new location instead of copying them. It recreates the directory structure in the new location. It also allows you to overwrite the existing files, or not.
Here is the function I made; it will likely need tweaking to work as a standalone script, since it relies of variables set by my program (eg: loc1 -- which dynamically changes in my program):
<?PHP
// loc1 is the path on the computer to the base directory that may be moved
define('loc1', 'C:/Program Files/Apache Group/Apache/htdocs', true);
// move a directory and all subdirectories and files (recursive)
// void dirmv( str 'source directory', str 'destination directory' [, bool 'overwrite existing files' [, str 'location within the directory (for recurse)']] )
function dirmv($source, $dest, $overwrite = false, $funcloc = NULL){
if(is_null($funcloc)){
$dest .= '/' . strrev(substr(strrev($source), 0, strpos(strrev($source), '/')));
$funcloc = '/';
}
if(!is_dir(loc1 . $dest . $funcloc))
mkdir(loc1 . $dest . $funcloc); // make subdirectory before subdirectory is copied
if($handle = opendir(loc1 . $source . $funcloc)){ // if the folder exploration is sucsessful, continue
while(false !== ($file = readdir($handle))){ // as long as storing the next file to $file is successful, continue
if($file != '.' && $file != '..'){
$path = $source . $funcloc . $file;
$path2 = $dest . $funcloc . $file;
if(is_file(loc1 . $path)){
if(!is_file(loc1 . $path2)){
if(!@rename(loc1 . $path, loc1 . $path2)){
echo '<font color="red">File ('.$path.') could not be moved, likely a permissions problem.</font>';
}
} elseif($overwrite){
if(!@unlink(loc1 . $path2)){
echo 'Unable to overwrite file ("'.$path2.'"), likely to be a permissions problem.';
} else
if(!@rename(loc1 . $path, loc1 . $path2)){
echo '<font color="red">File ('.$path.') could not be moved while overwritting, likely a permissions problem.</font>';
}
}
} elseif(is_dir(loc1 . $path)){
dirmv($source, $dest, $overwrite, $funcloc . $file . '/'); //recurse!
rmdir(loc1 . $path);
}
}
}
closedir($handle);
}
} // end of dirmv()
?>
This new function will be in 0.9.7 (the next release of File Manage) which should release sometime early February.
Hope this helps some people.
Remark for "php at stock-consulting dot com"'s note:
This depends on the operating system.
On windows-systems you can't rename a file to an existing destination (ok, with tools you can - but they unlink the exisiting one before).
rename() fails with PHP4 and PHP5 under Windows if the destination file exists, regardless of file permission settings. I now use a function similar to that of ddoyle [at] canadalawbook [dot] ca, which first tries rename(), checks if it returned FALSE and then uses copy()/unlink() if it failed.
However, copy() is, unlike rename(), NOT useable for "atomic updates". Another process may actually access the destination file while copy() is working. In such a case, the other process with perceive the file as empty or with incomplete content ("half written").
It is unclear what encoding the arguments of rename should have; For PHP 4.3, on a HFS+ filesystems, rename() did not handle UTF-8 strings, and returned an error.
On WinXP/PHP 5+, not only does rename() not follow the *nix rename as noted below, but other things (do not) happen. If you're trying to rename a directory, files within the directory will NOT be present in the renamed directory, though sub-directories WILL be present. Ultra-strange. And as noted, your 'old' directory will remain on the server totally intact, which can be very confusing.
To try and rename a folder on XP via PHP, I wound up using a workaround: first i used the copydirr() function posted by makarenkoa at ukrpost dot net on the "copy" page of the online manual to copy all folders and files within the original directory to the new one... and then to delete the original directory (and all files/folders beneath it), i used the delDir() function corrected by czambran at gmail dot com on the "rmdir" page of the online manual. Why didn't I use unlink()? Because, unlink does NOT work on Windows systems either (and even if it did work, its not recursive without extra coding).
So, all in all, rename() is pretty much a useless function if you are intending to rename a folder on an XP box.
I needed to move a file to another folder regardless if that file existed in the target already so I wrote a small piece to append a unique number to each file.
$rem = $_GET['file'];
$ticket = uniqid(rand(), true);
rename("$rem", "www/home/storefile/$ticket$rem");
the output looks like this - 6881432893ad4925a1.70147481filename.txt
This also helps if you want different versions of the file stored.
rename() definitely does not follow the *nix rename convention on WinXP with PHP 5. If the $newname exists, it will return FALSE and $oldname and $newname will remain in their original state. You can do something like this instead:
function rename_win($oldfile,$newfile) {
if (!rename($oldfile,$newfile)) {
if (copy ($oldfile,$newfile)) {
unlink($oldfile);
return TRUE;
}
return FALSE;
}
return TRUE;
}
Actually, I'm pretty sure that rename follows the convention of *nix rename(2) in overwriting the destination if it exists atomically (meaning that no other process will see the destination cease to exist, even for an instant). This is useful because it allows you to build a file as a temp file, then rename it to where you want it to be, and nobody sees the file when it's half done.
Probably rename($old, $new) with an existing new was caused by permission problems. I bet the other problems you had were the result of not calling clearstatcache(), which can cause PHP to act like a file exists though it has since been deleted.
To anyone wondering, rename($old, $new) returns FALSE if $new already exists. My script called for overwriting the file if it existed so I did this:
if(file_exists($new)) { unlink($new); }
$ok = rename($old, $new);
This did not work as expected. If $new actually existed then it worked fine. That is the file found at path $new was deleted and replaced with the file found at path $old. However, if $new did NOT exist then the result was the file at path $old vanished into oblivion. After debugging a bit, it seems that rename() was getting executed before the if-statement. So rename() moved $old to $new, THEN the if-statement evaluated to true and deleted the file I just moved. Anyway, this fixed it:
if(file_exists($new)) {
unlink($new);
$ok = rename($old, $new);
} else { $ok = rename($old, $new); }
Very strange ... I hope this helps somebody
Hello!
For unix/linux users: it is usefull to know that if you use rename() for a directory, the new one will be created with the current umask!
You can always chdir() to the parent directory of what you're renaming, and rename the directory or file directly. For example:
$oldWD = getcwd();
chdir($dirWhereRenameeIs);
rename($oldFilename, $newFilename);
chdir($oldWD);
If you rename one directory to another where the second directory exists as an empty directory it will not complain.
Not what I expected.
[pearcec@abe tmp]$ mkdir test1
[pearcec@abe tmp]$ mkdir test2
[pearcec@abe tmp]$ touch test1/test
[pearcec@abe tmp]$ php
<?php
rename("test1","test2");
?>
X-Powered-By: PHP/4.0.5
Content-type: text/html
[pearcec@abe tmp]$ ls -al
total 12
drwxr-xr-x 3 pearcec commnav 4096 Jun 15 13:17 .
drwxr-xr-x 18 pearcec commnav 4096 Jun 15 13:15 ..
drwxr-xr-x 2 pearcec commnav 4096 Jun 15 13:16 test2
[pearcec@abe tmp]$ ls -la test2/
total 8
drwxr-xr-x 2 pearcec commnav 4096 Jun 15 13:16 .
drwxr-xr-x 3 pearcec commnav 4096 Jun 15 13:17 ..
-rw-r--r-- 1 pearcec commnav 0 Jun 15 13:16 test
[pearcec@abe tmp]$
Note, that on Unix, a rename is a beautiful way of getting atomic updates to files.
Just copy the old contents (if necessary), and write the new contents into a new file, then rename over the original file.
Any processes reading from the file will continue to do so, any processes trying to open the file while you're writing to it will get the old file (because you'll be writing to a temp file), and there is no "intermediate" time between there being a file, and there not being a file (or there being half a file).
Oh, and this only works if you have the temp file and the destination file on the same filesystem (eg. partition/hard-disk).