<SOLVED> symlink creation issues - simple problem?

[tomcloyd]

I've never been at ease with the "ln" CLI command. It seems all but inscrutable in its complexities, and foils me every time I try to use it. I'm trying again tonight.

I come from Windows, where creating a link to another file in the very easy, and in fact available from the right-click menu. Very user-friendly. Nothing like this exists in Linus, so far as I can tell. I very much wish it did.

Meanwhile, I still need this functionality. I've dug through all the documentation I can find - the info page output, and the output from info coreutils 'ln invocation', and I still cannot get it right. I've studied a couple of tutorials on relative and absolute pathnames, and found them not useful to me, in that they didn't lead me to a working symlink creation command. I'm baffled as to why this simple operation is so elusive to me. Here's what I'm trying to do:

I have a file here: "/home/tomc/E-books/filex.pdf"

I want a link to it that will survive being moved to another location.

I've tried all these, and none actually work:

ln -s "filex.pdf" "link to filex.pdf"
ln -s "../filex.pdf" "link to filex.pdf"
ln -s "../../filex.pdf" "link to filex.pdf"
ln -s "../../../filex.pdf" "link to filex.pdf"

One of these should have worked, according to my understanding of the coreutils documentation, but alas...

I would greatly appreciate a working example of how to do this.

[AboveTheLogic]

Re: symlink creation issues - simple problem?

I just did a little experiment to do what you did, here are my results:

#Show working directory:
:~/test$ pwd
/home/ATL/test
#Create two directories: "test1" and "test2"
:~/test$ mkdir test1 test2

#Verify that they were created
:~/test$ ls        
test1 test2

#Create blank file "test.txt"
:~/test$ touch test.txt

#Add the text "test123" to the "test.txt" file:
:~/test$ echo "test123" > test.txt

#Verify that "test123" exists in that file:
:~/test$ cat test.txt
test123

#Open the "test1" directory"
:~/test$ cd test1/

#Create a symlink to the test.txt file in previous directory:
:~/test/test1$ ln -s /home/ATL/test/test.txt

#Navigate to previous directory
:~/test/test1$ cd ..

#List contents, test.txt file is still there
:~/test$ ls
test1 test2 test.txt

#Display contents of test1/test.txt file (the symlink)
:~/test$ cat test1/test.txt
test123
#This matches.

#Move the test.txt symlink from the "test1" directory to the "test2" directory:
:~/test$ mv test1/test.txt test2/

#Show contents of the test.txt symlink in the "test2" directory
:~/test$ cat test2/test.txt
test123
#This matches.

#Show that this file is indeed a symlink, not a copied file:
:~/test/test2$ ls -l
total 0
lrwxrwxrwx 1 ATL ATL 25 2009-06-21 23:00 test.txt -> /home/ATL/test/test.txt
:~/test/test2$

Success...

[tomcloyd]

Re: symlink creation issues - simple problem?

Very interesting, and helpful. I learned several things from your example. THANKS!

Now I'm off to give it a try.

t.

[tomcloyd]

Re: symlink creation issues - simple problem?

I have some puzzling results. In summary:

Your example works fine for me, using a text file. I get exactly the results you got: the link does exactly what it should, which opened.

However, my target files are PDF files, and these do NOT work. Using your precise method -

ln -s "{pathname}xxx.pdf" leads to the result I've been getting all night, with all methods I've tried - yours or mine: My PDF reader (and it doesn't matter which of the 3 installed I use) opens and displays this message:

"There was an error opening this document. This file cannot be found."

I have no idea why this is happening. Any ideas?

[AboveTheLogic]

Re: symlink creation issues - simple problem?

pdf seems to work for me, here are my results but using relative path instead of absolute path:

:~/test$ pwd
/home/ATL/test   
:~/test$ ls 
kmymoney-user.pdf test1 test2
:~/test$ md5sum kmymoney-user.pdf 
b4fd23e0a1a380ee669a954aee1e3c53 kmymoney-user.pdf
:~/test$ cd test1/            
:~/test/test1$ ln -s ../kmymoney-user.pdf 
:~/test/test1$ ls
kmymoney-user.pdf
:~/test/test1$ md5sum kmymoney-user.pdf
b4fd23e0a1a380ee669a954aee1e3c53 kmymoney-user.pdf
:~/test/test1$ cd ..
:~/test$ ls
kmymoney-user.pdf test1 test2
:~/test$ mv test1/kmymoney-user.pdf test2/
:~/test$ ls test1/
:~/test$ ls test2/
kmymoney-user.pdf
:~/test$ md5sum test2/kmymoney-user.pdf
b4fd23e0a1a380ee669a954aee1e3c53 test2/kmymoney-user.pdf
:~/test$ cd test2/
:~/test/test2$ ls -l
total 0
lrwxrwxrwx 1 ATL ATL 20 2009-06-22 09:47 kmymoney-user.pdf -> ../kmymoney-user.pdf
:~/test/test2$

I can then open dolphin and open the kmymoney-user.pdf file using the symlink in the test2 directory and it works fine

It sounds like a path problem for your symlink, can you post more details about your paths and your ls -l info?

[muzicman0]

Re: symlink creation issues - simple problem?

I come from Windows, where creating a link to another file in the very easy, and in fact available from the right-click menu. Very user-friendly. Nothing like this exists in Linus, so far as I can tell. I very much wish it did.

Ahhhhhh....but it does! If I understand what you are trying to do...if you open dolphin, and drag the file to another location (you can even do this across tabs), when you release the mouse button, a dialog box will ask you if you want to move, copy, etc...one of those options will be to link. I believe (although not 100% sure) that if you choose link, it just creates a symlink wherever you dropped the file.

[tomcloyd]

Re: symlink creation issues - simple problem?

I come from Windows, where creating a link to another file in the very easy, and in fact available from the right-click menu. Very user-friendly. Nothing like this exists in Linus, so far as I can tell. I very much wish it did.

Ahhhhhh....but it does! If I understand what you are trying to do...if you open dolphin, and drag the file to another location (you can even do this across tabs), when you release the mouse button, a dialog box will ask you if you want to move, copy, etc...one of those options will be to link. I believe (although not 100% sure) that if you choose link, it just creates a symlink wherever you dropped the file.

Well. Hmmm. I've been wondering for a while if it's time for new glasses for my aging eyes. We just may have answered that question! I had NEVER noticed that "link" option. Incredible. What it creates is a HARD LINK.

From the output of

info coreutils ‘ln invocation’

-

A "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 _is_ the file.

But, a hard link, if I understand correctly, is NOT a file copy. Just a pointer, as it were. Exactly what I'm after.

Ah, it's a good day for this Linux lover.

My thanks to you.