ShowDEV: My-Alternatives - Hacking update-alternatives to make user-level changes

Introducing My-Alternatives

• https://github.com/TekWizely/my-alternatives

My-Alternatives takes an honest run at making a useful tool to allow you to configure alternatives (see: update-alternatives) that only affect your local account / shell sessions.

No root/sudo

My-Alternatives does not require root / sudo privileges to use, as it creates and maintains user-owned alt root directories that store your alternative links.

Quick Example

Here's a quick example of using my-alterantives to configure a local override for the pager alternative:

confirm current system value for pager

$ which pager

/usr/bin/pager

take a closer look

$ ls -l /usr/bin/pager

lrwxrwxrwx root root  /usr/bin/pager -> /etc/alternatives/pager

$ ls -l /etc/alternatives/pager

lrwxrwxrwx  root  root  /etc/alternatives/pager -> /usr/bin/less

init my-alternatives

$ eval "$( my-alternatives init )"

configure pager

$ my-alternatives config pager

There are 2 choices for the alternative pager (providing ${MY_ALTS_ROOT}/bin/pager).

  Selection    Path            Priority   Status
------------------------------------------------------------
  1            /bin/more        50        
  2            /usr/bin/less    77        system value

Type selection number: 

select non-system value '/bin/more'

... Type selection number: 1

configured local alternative for pager: /bin/more

confirm updated value

$ which pager

/tmp/my-alts.abcd/bin/pager

take a closer look

$ ls -l "${MY_ALTS_ROOT}"/bin/pager "${MY_ALTS_ROOT}"/man/man1/pager.1.gz

lrwxrwxrwx  user  group  bin/pager -> /bin/more
lrwxrwxrwx  user  group  man/man1/pager.1.gz -> /usr/share/man/man1/more.1.gz

Per-Shell Alternatives

The example above shows how to create per-shell alternatives.

That is, using my-alternatives init without specifying a target directory results in the creation and use of a temporary directory that only the current shell session knows about.

User-Level Alternatives

You can configure user-level alternatives by providing a specific init directory i.e:

$ eval "$( my-alternatives init ~/.my-alts )"

More Information

Please see the Project Homepage for more inrmation.

Thanks for looking and please let me know if you have any questions!

-TekWizely