A very simple bookmarking system for file system navigation with bash. 

mk is a shell script, that marks the $(pwd) with the argument as a $KEY
It adds an entry into ~/.bookmarks and ~/.bookmarks_auto

bk is a shell function added to the bashrc, that invokes book, and passes
the $KEY:$VALUE to cd

bk is an eager match. It does not need to be the entirety of the $KEY to make 
a match. And if there are multiple matches, it will return the first $KEY it 
reaches in the ~/.bookmarks file. 

Example:

user@~/Downloads> mk download
user@~/Documents> mk documents

user@~> bk do 

# Will cd into download:$VALUE (~/Downloads)
# since it will be the first entry that matches

user@~> bk doc

# Will cd into documents:$VALUE (~/Documents)


This system is not packed with features. It is very simple, and it does have
auto completion. However, marked aliases will not show up for auto completion
until after a new $SHELL session has been started, after creating the alias.

To remove entries, you may manually view the ~/.bookmarks file, and the 
~/.bookmarks_auto with your favorite text editor, and remove the offending
alias lines. Each entry must be separated by a newline when/if you edit the file.