How to test for link to a link

readlinktest

I want to test whether a file is a link to another link. I tried readlink but it doesn't work the way I need it: 

ralph@bash4.4.12,1:~/subdir1 $ ll
lrwxrwxrwx 1 pi pi   13 Apr 10 14:34 hellolink -> subdir2/hello
lrwxrwxrwx 1 pi pi    9 Apr 10 14:34 hellolink2 -> hellolink
drwxr-xr-x 2 pi pi 4096 Apr 10 14:33 subdir2

Using readlink I now get either the canonicalized form of the ultimate target or the naked filename of the next link (hellolink):

ralph@bash4.4.12,1:~/subdir1 $ readlink -f hellolink2
/home/ralph/subdir1/subdir2/hello
ralph@bash4.4.12,1:~/subdir1 $ readlink hellolink2
hellolink

But what I need is the full path to the file that hellolink2 points at:

/home/ralph/subdir1/hellolink

Right now I'm doing something like this:

if [ -h "$(dirname hellolink2)/$(readlink hellolink2)" ] ; then 
            echo hellolink2 is a link
fi

That looks like a lot of overhead when I do it many times in a loop, using find to feed it the filenames.

Is there an easier way?

Best Answer

Use test -L (without readlink) to see if a file is a symbolic link.

if [ -L hellolink2 ]

Use realpath to get the absolute path of a symlink to a directory.

$ realpath hellolink2
/home/ralph/subdir1/hellolink
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