File and directory metadata

The file or directory metadata consists of information such as

Inode number
Access rights/permissions (file mode bits)
Size/number of blocks allocated)
Time of last access, last modification and last inode change (sometimes referred to as atime, mtime and ctime).
Device number
ID of file owner and group owner (uid, gid)
Time of birth
SELinux security context string

Access rights/permissions (file mode bits)

A file's or directory's access right bits can be changed with chmod.

Sticky bit

chmod a+t some_file

A directory With the sticky bit set that is writeable allows users to write files into it, but these files cannot be deleted or modified except by the user owning them.

This is particularly useful for the /tmp directory.

atime, mtime, ctime

A file in a typical Linux filesystem has three timestampes: atime (last access time), mtime (last modification time) and ctime (last change time).

The modification time is the last time that the data (content) of the file has changed.

The change time is the last time that the attributes of a file have changed.

With cp, the timestamps (also ctime?) can be preserved by using the --preserve=timestamps option.

touch can be used to change a file's atime and mtime, but not the ctime.

A file's atime, mtime and ctime are shown with one of the ls -l variants.