UNIX for Dummies Questions & Answers

Hi, trying to understand more about symblic link, when I compiled a program called "match" in one folder

Code:

~/downloadsoftware/

I want this program to be accessible like a system command by putting a symbolic link in

Code:

 /usr/bin/

Not by setting the $PATH method in .bashrc at this time.
What I did is:

Code:

$~/downloadsoftware/match> sudo ln -s match /usr/bin/match

I was hoping to create the command match in /usr/bin/. The fact is the link is there but not executable as in the local folder: ~/downloadsoftware/match which is executable. When I tried:

Code:

$>which match
$>

It shows nothing but match is in /usr/bin/. If I go to /usr/bin/ and do

Code:

$/usr/bin> sudo ln -s ~/downloadsoftware/match match
$>which match
$>/usr/bin/match

Why is it like this? I thought

Code:

ln -s /path/to/source/file /path/to/destination/file

should work for any circumstances. What did I miss? Thank you!

Do

Code:

ls -l /usr/bin/match

to see what you have done.
The /path/to/source/file must be absolute or relative to the /path/to/destination/.

Code:

ln -s match /usr/bin/match

would be relative to /usr/bin/ i.e. point to itself.

Code:

cd /usr/bin
ln -s ~/downloadsoftware/match match

or

Code:

ln -s ~/downloadsoftware/match /usr/bin/match

is correct, because the /path/to/source/file is absolute.

Thanks!
I did noticed sometimes that ls -l indicated the link is actually pointed to itself. It seems to me the trick is this statement

Code:

The /path/to/source/file must be absolute or relative to the /path/to/destination/.

but the man page does not provide enough information about this. More care should be taken next time to create a soft link. Thanks a lot!

The trick is, for symlinks, ln takes the path completely literally.

So if you do

Code:

ln -s ../whatever path/to/linkname

You might expect a link to ../../../whatever, since it's more folders up, right?

Nope, it just gives a link pointing to the path ../whatever. It doesn't extend it for you.

If you give it an absolute path, it can't make this mistake.

I think my misunderstanding is the relative path was assumed OK, and was used.