(PHP 4, PHP 5)
chmod — 改变文件模式
$filename
, int $mode
)
尝试将 filename 所指定文件的模式改成
mode 所给定的。
注意 mode 不会被自动当成八进制数值，而且也不能用字符串（例如 "g+w"）。要确保正确操作，需要给
mode 前面加上 0：
<?php
chmod("/somedir/somefile", 755); // 十进制数，可能不对
chmod("/somedir/somefile", "u+rwx,go+rx"); // 字符串，不对
chmod("/somedir/somefile", 0755); // 八进制数，正确的 mode 值
?>
mode 参数包含三个八进制数按顺序分别指定了所有者、所有者所在的组以及所有人的访问限制。每一部分都可以通过加入所需的权限来计算出所要的权限。数字 1
表示使文件可执行，数字 2 表示使文件可写，数字 4
表示使文件可读。加入这些数字来制定所需要的权限。有关 UNIX 系统的文件权限可以阅读手册“man 1
chmod”和“man 2 chmod”。
<?php
// Read and write for owner, nothing for everybody else
chmod("/somedir/somefile", 0600);
// Read and write for owner, read for everybody else
chmod("/somedir/somefile", 0644);
// Everything for owner, read and execute for others
chmod("/somedir/somefile", 0755);
// Everything for owner, read and execute for owner's group
chmod("/somedir/somefile", 0750);
?>
成功时返回 TRUE， 或者在失败时返回 FALSE.
Note:
当前用户指的是执行 PHP 的用户。很可能和通常的 shell 或者 FTP 用户不是同一个。在大多数系统下文件模式只能被文件所有者的用户改变。
Note: 此函数不能作用于远程文件，被检查的文件必须是可通过服务器的文件系统访问的。
Note: 当安全模式打开的时候，PHP 会检查所操作的文件是否和正在执行的脚本具有相同的 UID （所有者）。要注意的是，不能修改 SUID，SGID 和 sticky bits。
filename
Path to the file.
mode
Note that mode is not automatically
assumed to be an octal value, so strings (such as "g+w") will
not work properly. To ensure the expected operation,
you need to prefix mode with a zero (0):
<?php
chmod("/somedir/somefile", 755); // decimal; probably incorrect
chmod("/somedir/somefile", "u+rwx,go+rx"); // string; incorrect
chmod("/somedir/somefile", 0755); // octal; correct value of mode
?>
The mode parameter consists of three octal
number components specifying access restrictions for the owner,
the user group in which the owner is in, and to everybody else in
this order. One component can be computed by adding up the needed
permissions for that target user base. Number 1 means that you
grant execute rights, number 2 means that you make the file
writeable, number 4 means that you make the file readable. Add
up these numbers to specify needed rights. You can also read more
about modes on Unix systems with 'man 1 chmod'
and 'man 2 chmod'.
<?php
// Read and write for owner, nothing for everybody else
chmod("/somedir/somefile", 0600);
// Read and write for owner, read for everybody else
chmod("/somedir/somefile", 0644);
// Everything for owner, read and execute for others
chmod("/somedir/somefile", 0755);
// Everything for owner, read and execute for owner's group
chmod("/somedir/somefile", 0750);
?>
成功时返回 TRUE， 或者在失败时返回 FALSE.
Note:
The current user is the user under which PHP runs. It is probably not the same user you use for normal shell or FTP access. The mode can be changed only by user who owns the file on most systems.
Note: 此函数不能作用于远程文件，被检查的文件必须是可通过服务器的文件系统访问的。
Note:
When 安全模式 is enabled, PHP checks whether the files or directories you are about to operate on have the same UID (owner) as the script that is being executed. In addition, you cannot set the SUID, SGID and sticky bits.