added instructions to view bookmarks in self documentation
added default initializations to prevent injections of outside variables
use ln -f option to avoid having to do existence check ourselves
changed existence check to symlink check before rm
added -pv options to mkdir
added -pv to mkdir in _to
removed default bookmark name creation since ln handles that automatically
simplified code, made sed input sanitation consistent
made -r option safer by trimming to path head
moved safety checks before -r, added messages on failure
changed output message
prepended user input to commands with -- and other safety changes
more command argument guards
get full path for third argument of -b
simplified bookmark printing
simplified bookmark printing and added return value for failure
added parameter guards
added safety checks for invalid bookmark names
added special case for /
added guards to prevent breaking on file completion with paths starting with a -