see also :
link
ln
[OPTION]... [-T] TARGET LINK_NAME (1st
form)
ln [OPTION]... TARGET (2nd form)
ln [OPTION]... TARGET... DIRECTORY (3rd
form)
ln [OPTION]... -t DIRECTORY TARGET...
(4th form)
Step 2
GNU utilities are primarily documented with info
pages. From the GNU ln info page:
‘-L’
‘--logical’
If -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.
So this simply dereferences symbolic links given as source arguments.
If you are not in the same directory as the target you must make sure you use the absolute path.
ln -s foo/bar baz/quux # fails
ln -s ~/foo/bar baz/quux # succeeds
ln can take either absolute or relative pathnames;
the difference matters for symbolic links, but since you asked to
make a hard link, it will resolve to the same file either way.
Check the ls -li output on ~/abc and
~/download/abc -- you'll see that the link count is
2 and the inode number is the same for both files.
via shell-builtins (and globoperator)
from l in /from/*.so; do ln -s "$l"; done
via find
find /from/ -name "*.so" -exec ln -s '{}' ';'
doing it via find is better since it works better
for huge amount of files.
It does not actually fail. It creates your link inside the given directory:
% mkdir dir_1 dir_2
% ln -s dir_1 symlink_dir
% ln -s dir_2 symlink_dir
% ls -l
total 0
drwxr-xr-x 2 user group 60 Oct 16 12:47 dir_1
drwxr-xr-x 2 user group 40 Oct 16 12:47 dir_2
lrwxrwxrwx 1 user group 5 Oct 16 12:47 symlink_dir -> dir_1
% ls -l dir_1
total 0
lrwxrwxrwx 1 user group 5 Oct 16 12:47 dir_2 -> dir_2
This behaviour is described in the manpage:
ln [OPTION]... TARGET... DIRECTORY (3rd form)
...
In the 3rd and 4th forms, create links to each TARGET in DIRECTORY.
However, this link fails to link back to dir_2 as it is not set properly. This is also expected behaviour though, and not meant to fail. From the manpage:
Symbolic links can hold arbitrary text; if later resolved, a relative link is interpreted in relation to its parent directory.
By the way, it works the same way for me even with
-sv. Maybe you are using a different implementation
of ln. Are you sure you are not using
-T? Maybe that is set in your
~/.bashrc/~/.zshrc/etc. Try which
ln.
The proper way to do this is to use the
--no-dereference option like so.
$ ln -snf foo2 bar
This causes ln to treat the existing symlink as a
file. Otherwise, it dereferences bar to
foo1, descends into foo1 and uses the
original TARGET name as the LINK_NAME
and that's why you end up with a symlink to foo2
being created inside the foo1 directory. The manpage
on ln states the following...
-n, --no-dereference
treat LINK_NAME as a normal file if it is a symbolic link to a
directory
Below is the shell output on my Arch Linux desktop with version
8.21 of ln with and without the
--no-dereference option, I got the same results you
did witout the --no-dereference option, but using
the --no-dereference option it worked as expected.
$ mkdir foo1 foo2
$ ln -s foo1 bar
$ ls -l bar
lrwxrwxrwx 1 drew users 4 Sep 17 12:51 bar -> foo1
$ ln -sf foo2 bar
$ ls -l bar
lrwxrwxrwx 1 drew users 4 Sep 17 12:51 bar -> foo1
$ ls -l foo1
total 0
lrwxrwxrwx 1 drew users 4 Sep 17 12:51 foo2 -> foo2
$ ln -snf foo2 bar
$ ls -l bar
lrwxrwxrwx 1 drew users 4 Sep 17 12:52 bar -> foo2
From the /bar directory, to create all symlinks for everything but these extensions.
find ../foo/ -type f ! -name '*.txt' ! -name '*.baz' -exec ln -s '{}' \;
And then to copy all the extensions, same command for the most part.
find ../foo/ -type f \( -name "*.txt" -o -name "*.baz" \) -exec cp '{}' ./ \;
Edit: Copy entire directory structure, symlink some files, copy others. Wasn't sure if this was possible at first with a single command, but just learned some other handy tricks with find.
find foo/ -type d -printf "mkdir -vp 'bar/%p'\n" -o -type f ! -name "*.txt" ! -name "*.baz" -printf "ln -vs '../%p' 'bar/%p'\n" -o -type f \( -name "*.txt" -o -name "*.baz" \) -printf "cp -v %p bar/%p\n" | sh
mv bar/foo/* bar/ && rm -R bar/foo/
Only important thing to note is when making the symbolic link you give the actual path the links will take to relate to foo/. My example shows relative links when they are side by side (could also make absolute symbolic links as well).
Use this command:
ls *txt | xargs -I R1 sh -c "cat R1 | xargs -I R2 ln -sf R2 R1"
Replace ls *txt with something that will output the
list of text files that should be symbolic links. For example,
find . -name "*txt" would list all *txt files in or
under the current directory.
A soft link is enough for your purpose. You simply need to omit the trailing slash, i.e.
ln -s ~/me
You should be able to edit the Makefile and accomplish this quickly.
NOTE - This assumes that the Makefile was made by GNU Autotools. According to the Cfengine tarball, they do.
First, open the Makefile and look for the flag
LDFLAGS. It should look something like this:
LDFLAGS=-lfoo -lbar
Append to that listing -ldl. This adds a reference
to the Dynamic Loading library.
Recompile, and the linker should be able to do it's job.
The LIBS environment variable is an environment variable that
tells ./configure what extra libraries are needed,
which it then sticks into the Makefile (so, to answer your
question, ./configure doesn't actually run the
linker - it makes the Makefile, which runs gcc
with the parameters it got from ./configure).
So, use LIBS=-ldl && ./configure.
Yes, it is true! To use /bigdata/backup as if it was
/data/backup you can use these commands in a
terminal.
First, as you already have a /data/backup directory,
move everything in it to /bigdata/backup:
mv /data/backup/* /bigdata/backup
Then delete your old directory:
rm -r /data/backup
Now you can link the directories with:
ln -s /bigdata/backup /data/backup
This way, /data/backup is essentially just a
redirect to /bigdata/backup; it's space on disk is
negligible.
Try find / -samefile /file/to/compare.
There were a similar question: Finding all symbolic and hard links to a file on UNIX
Add --backup=numbered to ln and .~n~
will be appended if a name already exist.
In the 1st form, create a link to TARGET with the name LINK_NAME. In the 2nd form, create a link to TARGET in the current directory. In the 3rd and 4th forms, create links to each TARGET in DIRECTORY. Create hard links by default, symbolic links with --symbolic. By default, each destination (name of new link) should not already exist. When creating hard links, each TARGET must exist. Symbolic links can hold arbitrary text; if later resolved, a relative link is interpreted in relation to its parent directory.
Mandatory
arguments to long options are mandatory for short options
too.
--backup[=CONTROL]
make a backup of each existing destination file
-d, -F, --directory
allow the superuser to attempt to hard link directories (note: will probably fail due to system restrictions, even for the superuser)
-f, --force
remove existing destination files
-i, --interactive
prompt whether to remove destinations
-L, --logical
dereference TARGETs that are symbolic links
-n, --no-dereference
treat LINK_NAME as a normal file if it is a symbolic link to a directory
-P, --physical
make hard links directly to symbolic links
-r, --relative
create symbolic links relative to link location
-s, --symbolic
make symbolic links instead of hard links
-S, --suffix=SUFFIX
override the usual backup suffix
-t, --target-directory=DIRECTORY
specify the DIRECTORY in which to create the links
-T, --no-target-directory
treat LINK_NAME as a normal file always
-v, --verbose
print name of each linked file
--version
output version information and exit
The backup
suffix is ’~’, unless set with
--suffix or SIMPLE_BACKUP_SUFFIX. The
version control method may be selected via the
--backup option or through the
VERSION_CONTROL environment variable. Here are the values:
none, off
never make backups (even if --backup is given)
numbered, t
make numbered backups
existing, nil
numbered if numbered backups exist, simple otherwise
simple, never
always make simple backups
Using -s ignores -L and -P. Otherwise, the last option specified controls behavior when a TARGET is a symbolic link, defaulting to -P.
Copyright © 2012 Free Software Foundation, Inc. License GPLv3+:
GNU GPL version 3 or later
<http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute
it. There is NO WARRANTY, to the extent permitted by law.
Report ln bugs to bug-coreutils[:at:]gnu[:dot:]org
GNU coreutils home page:
<http://www.gnu.org/software/coreutils/>
General help using GNU software:
<http://www.gnu.org/gethelp/>
Report ln translation bugs to
<http://translationproject.org/team/>
link , symlink
The full documentation for ln is maintained as a Texinfo manual. If the info and ln programs are properly installed at your site, the command
info coreutils 'ln invocation'
should give you access to the complete manual.
Written by Mike Parker and David MacKenzie.