On 19Jun2010 21:35, Patrick O'Callaghan <pocallaghan@xxxxxxxxx> wrote:
| A script I'm writing needs to work out the target of a symbolic link,
| i.e. given:
|
| $ touch foo
| $ ln -s foo bar
|
| the function should print bar when given foo as a parameter.
>From your examples below, you mean "print foo when given bar as a
parameter". I'll presume you meant that.
| The manual
| says "ls -L" should do this,
No, it doesn't. It prints information _about_ foo, not "foo". i.e. it does a
stat(2) instead of an lstat(2) call. From the manual:
-L, --dereference
when showing file information for a symbolic link, show information
for the file the link references rather than for the link itself
So plain "ls -ld bar" shows that it is a symlink. "ls -ldL bar" shows
information about "foo" (not _not_ its name - it just uses "bar" to
access through the symlink - the OS reads the string "foo" and follows
it to the file "bar" - the ls command never sees it).
| but it doesn't seem to work:
|
| $ touch foo
| $ ln -s foo bar
| $ ls -l foo bar
| lrwxrwxrwx 1 poc poc 3 Jun 19 21:32 bar -> foo
| -rw-rw-r-- 1 poc poc 0 Jun 19 21:32 foo
| $ ls -L bar
| bar
|
| (should give foo)
|
| Have I misunderstood what "ls -L" does?
Yes.
| Is there a bug?
No.
| And is there a better way of doing this?
man 1 readlink
linkvalue=`readlink bar` # gets "foo"
The readlink command is a GNU command - not portable to UNIX systems which
don't have the GNU commands grafted on. Of course it is a one line perl
or python script do implement this on a system with no readlink command.
Cheers,
--
Cameron Simpson <cs@xxxxxxxxxx> DoD#743
http://www.cskk.ezoshosting.com/cs/
We all lie, cheat and steal, mostly a little, sometimes a lot. Relax.
- Henry Prange - biker/thermoregulation physiologist
DoD#0821, <prange@xxxxxxxxxxxxxxxxxxxxxx>
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