Create a Hash-like structure with Bash

This is pretty cool and worth sharing. In Bash you can use declare -A VarName to create a Hash-like structure which you can use to store key / value pairs in.

Lets take a look:

$ declare -A CapitalCity
$ CapitalCity[France]="Paris"
$ echo "${CapitalCity['France']}"
Paris

Pretty damn cool. I discovered this trick in Jason Brittains 'Bash as a Modern Programming Language' presentation. Slides are available.

Enumerate set values from declare

To get a list of set values you can run declare -A and it will print a list similar to the following:

$ declare -A
declare -A BASH_ALIASES='()'
declare -A BASH_CMDS='()'
declare -A CapitalCity='([France]="Paris" )'
declare -A _xspecs='(... <many many> ...)'