What is it?

BashHash is a BASH loadable built-in (like a plug-in or module) that exposes some useful features of GLib's GHashTable interface. It allows one to create and manipulate hash tables in the BASH process space using a true hash table implementation.

Requirements: bashhash uses GLib version 2.16 or later.

Documentation - Loading/Unloading a BASH built-in 

# to load a loadable built-in
bash$ enable -f /path/to/binary/builtin builtin

# to unload a built-in
bash$ enable -d builtin
Documentation - Subcommands
insert
Insert key/value pairs into a hash table. When you insert an entry into a table that does not yet exist, the table is created. Multiple key/value pairs can be specified on the command line. Ensure that you quote properly so that bash doesn't split your data in undesired ways.
lookup
Print the values associated with specified keys. You can specify multiple keys to print.
remove
Remove the key/value pair associated with the specified keys. Multiple keys may be specified. Deleting all key/value pairs in a table does not delete the table itself. To delete a table, you must use destroy.
destroy
Free all memory associated with a table. This deletes all key/value pairs in the table as well as the table itself.
keys
Print the list of keys in the specified table
tables
Print the list of existing tables
dupkey
Sets your preference for how duplicate keys are handled. Valid settings are either 'fail' or 'overwrite.' Without any parameters, the current setting will be displayed. The default is to overwrite.
iterate
Create an iterator. This allows you to easily loop through all key/value pairs in the table entirely inside the bash process space. The only other way to get data from a table into a variable is via command substitution which requires a subshell.
Example 1 - Inserting data 

bashhash insert MyTable1 key1 value1 key2 value2 keyN valueN

bashhash insert MyTable1 "Key With Spaces" "Value With Spaces"

bashhash insert MyFiles hosts "$(</etc/hosts)" resolve.conf "$(</etc/resolv.conf)"
Example 2 - Performing Lookups 

bashhash lookup MyTable1 key1 keyN

# command substitution
HOSTSFILE=$( bashhash lookup MyFiles hosts )
Example 3 - Removing key/value pairs 

bashhash remove MyTable1 keyN key2

bashhash remove MyFiles hosts
Example 4 - Destroying tables 

bashhash destroy MyTable1 MyFiles
Example 5 - Iterators 

while bashhash iterate MyTable1 MyIter1 MyKey MyValue
do

	echo "'$MyKey'" is the key for "'$MyValue'"

done