EDLN

[Geoffrey]

I found this as a solution to a problem of changing symlinks when repackaging.

Usage edln /path/to/symlink /symlink/target

Introduction
============

edln is a simple readline-based utility for interactively editing the target
of a symbolic link. This is most useful if you only need to make a relatively
minor change to the symlink.


Using edln
==========

Typically, edln is called with a single argument -- the path to the symlink
to be edited. For example, if you have a symlink 'foo' that points to the
file '/usr/local/bin/foo-1.0', and you want to update it to point to the file
'/usr/local/bin/foo-1.1' instead, you would invoke edln as follows (where the
'$' denotes the shell prompt):

$ edln foo
New target: /usr/local/bin/foo-1.0

As you can see, edln displays the current symlink target, and allows you to
edit it. Now press the Backspace key once to delete the '0' character, then
press the '1' key to insert the '1' character, and finally, press the Enter
key to complete the update.

As edln relies on GNU Readline for editing, it supports much more
sophisticated editing than demonstrated in the simple example above.
Refer to the GNU Readline User Manual for further details:

http://cnswww.cns.cwru.edu/php/chet/rea ... erman.html

As a final note, edln also supports a two-argument invocation, which is
mostly equivalent to 'ln -sf'. That is, 'edln foo /usr/local/bin/foo-1.1' has
the same effect as 'ln -sf /usr/local/bin/foo-1.1 foo'.

However, when the symlink 'foo' points to a directory, the behavior is
different. For example, suppose 'foo' points to 'dir1', and you want to
change it to point to 'dir2' instead. Running 'ln -sf dir2 foo' will not
accomplish this -- instead, it will create inside 'dir1' a new symlink 'dir2'
(that points to 'dir2'). In contrast, running 'edln foo dir2' will have the
desired effect.


Pre-Built Binaries
==================

Binaries for select platforms are available at:

https://github.com/jjlin/edln/downloads

For other platforms, edln should not be difficult to build from source.


Building From Source
====================

A simple makefile is provided with the edln source code, available at:

https://github.com/jjlin/edln/

You need to ensure that the GNU Readline development packages are installed
(e.g., 'libreadline-dev' on Debian/Ubuntu, or 'readline-devel' on RHEL/CentOS).

You may also need to ensure that the GNU Ncurses package is installed,
particularly on RHEL/CentOS, where linking with the -lncurses flag is
required. On RHEL/CentOS, the package name is 'ncurses'.

Exact details for building from source on other Unix-like systems may vary,
but should be quite similar.