[SOLVED] ln -s syntax

centguy · 11-11-2021, 10:45 AM

Are these two commands equivalent?

Quote:

ln -s /path-to-somewhere/a-file .

and

Quote:

ln -s /path-to-somewhere/a-file

The first one has a dot. at the end. It seems they are the same but I cannot be sure.

HappyTux · 11-11-2021, 11:06 AM

No they are not the same the second is a failed command. The first no clue why it would be linked to . it is usually short for one level of the directory structure your current directory the .. the directory above. Normally you link the real file to the file to be linked ln -s /path/to/real/file /path/to/linked/file

Code:

zeus@bullseye-raspi:~$ touch test.txt
zeus@bullseye-raspi:~$ ln -s test.txt 
ln: failed to create symbolic link './test.txt': File exists
zeus@bullseye-raspi:~$ ln -s test.txt test2.txt
zeus@bullseye-raspi:~$ ls -l test*
lrwxrwxrwx 1 zeus zeus 8 Nov 11 12:59 test2.txt -> test.txt
-rw-r--r-- 1 zeus zeus 0 Nov 11 12:58 test.txt
zeus@bullseye-raspi:~$ cd .
zeus@bullseye-raspi:~$ cd ..
zeus@bullseye-raspi:/home$

Edit: Now it popped into my head the second command links to a file that is not there only a link.

Code:

zeus@bullseye-raspi:~$ rm test*
zeus@bullseye-raspi:~$ ln -s test.txt 
zeus@bullseye-raspi:~$ ls -l test*
lrwxrwxrwx 1 zeus zeus 8 Nov 11 13:16 test.txt -> test.txt

Not of any use I can see except as a method of have that name in place as there will be no contents in the link, the usual idea with a link is to have the same contents in two differently named files without using the space for the duplicate being linked.

michaelk · 11-11-2021, 11:24 AM

Quote:

zeus@bullseye-raspi:~$ touch test.txt
zeus@bullseye-raspi:~$ ln -s test.txt
ln: failed to create symbolic link './test.txt': File exists

Your example fails because your trying to create a link in the same directory as the source. since the OP specified the path to the file I would assume the current working directory is not the same.

From the man page it should be the same since ln will create a link of the same name in the current working directory or the specified directory which by the . is the current working directory.

HappyTux · 11-11-2021, 11:27 AM

Quote:

Originally Posted by michaelk

Your example fails because your trying to create a link in the same directory as the source. since the OP specified the path to the file I would assume the current working directory is not the same.

From the man page it should be the same since ln will create a link of the same name in the current working directory or the specified directory which by the . is the current working directory.

Yes I seen this when it popped into my head about me having created the file first and tried it as my edit shows.

pan64 · 11-11-2021, 01:20 PM

yes, that is an ugly exception (so no other tools - like cp, mv - will take current dir as default like this). That's why I don't use it, but actually it works.

centguy · 11-11-2021, 09:15 PM

Cool. Thanks!

MadeInGermany · 11-12-2021, 09:27 AM

Quote:

Originally Posted by centguy

Are these two commands equivalent?
...
The first one has a dot. at the end. It seems they are the same but I cannot be sure.

Yes they are equivalent.
The dot is needed in case there are two or more link targets.

Code:

ln -s /path-to-somewhere/a-file /path-to-somewhere/b-file .

Or

Code:

ln -s /path-to-somewhere/*.txt .

ondoho · 11-13-2021, 01:18 AM

Quote:

Originally Posted by centguy

Cool. Thanks!

Please mark your thread SOLVED (see my signature).