[lsb-discuss] readlink

[Nelson H. F. Beebe]

Craig Scott <audiofanatic at gmail.com> writes today:

>> readlink on its own as a naked command actually won't do it for
>> you. It needs to be called repeatedly until it returns an empty string
>> before you can be sure all symbolic links have been followed.

Not so: use "readlink -f" or "readlink -e":

% file foo.l?
foo.l1: empty
foo.l2: symbolic link to `foo.l1'
foo.l3: symbolic link to `foo.l2'
foo.l4: symbolic link to `foo.l3'
foo.l5: symbolic link to `foo.l4'

% readlink --version
readlink (GNU coreutils) 8.9
...

% readlink foo.l5
foo.l4

% readlink -f foo.l5
/home/jones/foo.l1

% readlink -e foo.l5
/home/jones/foo.l1

% readlink --help
Usage: readlink [OPTION]... FILE
Print value of a symbolic link or canonical file name

  -f, --canonicalize            canonicalize by following every symlink in
                                every component of the given name recursively;
                                all but the last component must exist
  -e, --canonicalize-existing   canonicalize by following every symlink in
                                every component of the given name recursively,
                                all components must exist
  -m, --canonicalize-missing    canonicalize by following every symlink in
                                every component of the given name recursively,
                                without requirements on components existence
  -n, --no-newline              do not output the trailing newline
  -q, --quiet,
  -s, --silent                  suppress most error messages
  -v, --verbose                 report error messages
      --help     display this help and exit
      --version  output version information and exit

...

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- Nelson H. F. Beebe                    Tel: +1 801 581 5254                  -
- University of Utah                    FAX: +1 801 581 4148                  -
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