linux 文件权限：数字和`rwx`序列对应关系

[licoded]

reference link: Fun with Numbers in chmod

Here's a list of some common settings, numerical values and their meanings:

• -rw------- (600) -- Only the user has read and write permissions.
• -rw-r--r-- (644) -- Only user has read and write permissions; the group and others can read only.
• -rwx------ (700) -- Only the user has read, write and execute permissions.
• -rwxr-xr-x (755) -- The user has read, write and execute permissions; the group and others can only read and execute.
• -rwx--x--x (711) -- The user has read, write and execute permissions; the group and others can only execute.
• -rw-rw-rw- (666) -- Everyone can read and write to the file. Bad idea.
• -rwxrwxrwx (777) -- Everyone can read, write and execute. Another bad idea.

Here are a couple common settings for directories:

• drwx------ (700) -- Only the user can read, write in this directory.
• drwxr-xr-x (755) -- Everyone can read the directory, but its contents can only be changed by the user.