Sinewalker dotfiles changes

Here I describe my changes to the dotfiles script. My intention here is to keep dotfiles itself as generic as possible, so that suitable Pull Requests could be made to Cowboy's original. That is: only mechanism enhancements are made, not policy.

There are two exceptions:

• when cloning dotfiles for the first time, I have updated the fall-back GitHub user name to be sinewalker instead of cowboy:

  git clone --recursive git://github.com/${github_user:-sinewalker}/dotfiles.git $DOTFILES

• I have updated the banner at the very start of dotfiles, that prints with a link to Ben Alman's web site if we are running without the "source" option. It retains this and his copyright notice, and add's my own

.bashrc

• added lssrc function to list the files in ${DOTFILES}/source/ which are picked up by the existing src function

  The src function has an optional parameter to specify a file to source, and my lssrc just lists what you can source, using the same globbing pattern that src does (so it only picks up ${DOTFILES}/source/*.sh; any other files in there will be skipped). It lists them without the .sh extension to be clear about how you specify it to src.

• added bash completion function for src which picks valid source/*.sh files formatted so that src can source them

• before actually calling src to source the files, test whether Bash is running in POSIX mode. If so then don't bother to source the files:

  • There are many Bash-isms in the code which fail when running in POSIX because they are not compatible with the standard
  • If bash has been started in POSIX mode, it's likely because it was started as /bin/sh in a sub-shell, so the system's not interactive anyway

linking

Dotfiles links files within link/ to their home-directory locations.

It also now correctly links files in config/ to the system application configuration directory (usually ~/.config, or whichever is specified by the $XDG_CONFIG variable on free-desktop systems like KDE. You can override this by setting $CONFIG near the start of bin/dotfiles but it should pick the correct location no matter which operating system is running.

In addition to these, I also link library files within $HOME/lib. That's a Policy descision. You can change where it goes by altering the value of $LIB near the start of bin/dotfiles.

initialisation

OS/Distribution detection

• added is_distribution functions for detecting Unix flavours that this project supports

That is: is_suse, is_redhat6, is_redhat7 and so on.

Also I updated is_ubuntu to use lsb_release -i for detecting "buntu" in the Linux distribution, rather than rely on the content of /etc/issue which could be changed. This also matches all the *buntu Ubuntu flavours, ubuntu, kubuntu, edubuntu and so on.

• expanded get_os to use the additional is_os functions

• is_exe is not used by dotfiles directly, but it /is/ used by initialisation modules. It tests that it's argument can be run as a command.

Other enhancements

Moved functions that are purely to do with bootstrapping Dotfiles and initialising environments, to after the point where the code bails for the source mode.

All functions in dotfiles were updated to move their comment lines into $FUNCDESC document strings, so that whence funcname and describe funcname show descriptive details. All non-trivial, interactive functions in the entire project will adopt this $FUNCDESC pattern. See Self-documenting functions.

All functions that are implementation helpers were renamed to start with two underscores, e.g. the prompt helpers prompt_thing have been renamed to __prompt_thing to indicate they are not meant for interactive use. They also may not have $FUNCDESC if they're trivial.