Linux Permissions (Chmod) Calculator

Easily calculate Linux file permissions by selecting checkboxes for Owner, Group, and Public. Get the Octal (e.g., 755) and Symbolic (e.g., -rwxr-xr-x) notation instantly.

常见问题

What do chmod 755 and chmod 777 mean?

chmod 755 means the owner has read, write and execute permissions (7=rwx), while group and others have read and execute (5=r-x). chmod 777 gives everyone full read, write and execute permissions, which is generally not recommended due to security risks.

What do rwx mean in Linux file permissions?

r (read) = 4, w (write) = 2, x (execute) = 1. Sum the values to get the octal digit: rwx = 4+2+1 = 7, r-x = 4+0+1 = 5.

What's the difference between chmod and chown?

chmod modifies the access permissions (read/write/execute) of a file or directory, while chown modifies the owner and group. Together they fully control file access.

What are setuid, setgid and the sticky bit?

setuid (4000) runs the file as its owner; setgid (2000) runs it as its group, or makes new files in a directory inherit the directory's group; sticky bit (1000) prevents non-owners from deleting files in a directory (commonly used on /tmp).