diff options
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/coreutils.texi | 49 |
1 files changed, 44 insertions, 5 deletions
diff --git a/doc/coreutils.texi b/doc/coreutils.texi index 0bfbd5689..b10cc100c 100644 --- a/doc/coreutils.texi +++ b/doc/coreutils.texi @@ -8753,6 +8753,11 @@ On a @acronym{GNU} system, this command acts like @samp{ln --directory not specified by @acronym{POSIX}, and the @command{link} command is more portable in practice. +If @var{filename} is a symbolic link, it is unspecified whether +@var{linkname} will be a hard link to the symbolic link or to the +target of the symbolic link. Use @command{ln -P} or @command{ln -L} +to specify which behavior is desired. + @exitstatus @@ -8808,8 +8813,10 @@ A @dfn{hard link} is another name for an existing file; the link and the original are indistinguishable. Technically speaking, they share the same inode, and the inode contains all the information about a file---indeed, it is not incorrect to say that the inode @emph{is} the -file. On all existing implementations, you cannot make a hard link to -a directory, and hard links cannot cross file system boundaries. (These +file. Most systems prohibit making a hard link to +a directory; on those where it is allowed, only the super-user can do +so (and with caution, since creating a cycle will cause problems to many +other utilities). Hard links cannot cross file system boundaries. (These restrictions are not mandated by @acronym{POSIX}, however.) @cindex dereferencing symbolic links @@ -8821,9 +8828,13 @@ refers to a different file, by name. When most operations (opening, reading, writing, and so on) are passed the symbolic link file, the kernel automatically @dfn{dereferences} the link and operates on the target of the link. But some operations (e.g., removing) work on the -link file itself, rather than on its target. The owner, group, and -mode of a symlink are not significant to file access performed through -the link. @xref{Symbolic Links,,, +link file itself, rather than on its target. The owner and group of a +symlink are not significant to file access performed through +the link, but do have implications on deleting a symbolic link from a +directory with the restricted deletion bit set. On the GNU system, +the mode of a symlink has no significance and cannot be changed, but +on some BSD systems, the mode can be changed and will affect whether +the symlink will be traversed in file name resolution. @xref{Symbolic Links,,, libc, The GNU C Library Reference Manual}. Symbolic links can contain arbitrary strings; a @dfn{dangling symlink} @@ -8878,6 +8889,14 @@ Remove existing destination files. @cindex prompting, and @command{ln} Prompt whether to remove existing destination files. +@item -L +@itemx --logical +@opindex -L +@opindex --logical +If @option{-s} is not in effect, and the source file is a symbolic +link, create the hard link to the file referred to by the symbolic +link, rather than the symbolic link itself. + @item -n @itemx --no-dereference @opindex -n @@ -8899,6 +8918,17 @@ just like a directory. This option is weaker than the @option{--no-target-directory} (@option{-T}) option, so it has no effect if both options are given. +@item -P +@itemx --physical +@opindex -P +@opindex --physical +If @option{-s} is not in effect, and the source file is a symbolic +link, create the hard link to the symbolic link itself. On platforms +where this is not supported by the kernel, this option creates a +symbolic link with identical contents; since symbolic link contents +cannot be edited, any file name resolution performed through either +link will be the same as if a hard link had been created. + @item -s @itemx --symbolic @opindex -s @@ -8920,6 +8950,15 @@ Print the name of each file after linking it successfully. @end table +@cindex hard links to symbolic links +@cindex symbolic links and @command{ln} +If @option{-L} and @option{-P} are both given, the last one takes +precedence. If @option{-s} is also given, @option{-L} and @option{-P} +are silently ignored. If neither option is given, then this +implementation defaults to @option{-P} if the system @code{link} supports +hard links to symbolic links (such as the GNU system), and @option{-L} +if @code{link} follows symbolic links (such as on BSD). + @exitstatus Examples: |