# Functional shell: a minimal toolbox

I already wrote a post about adopting a functional programming style in Bash scripts. Here I want to explore how to build a minimal, reusable functional toolbox for my bash scripts, avoiding redefinition of base functional bricks whenever I need them.

So, in short: I wish I could write a scripts (say use-functional-bricks.sh) like the following

referring to “globally” available functions map and reduce(and maybe others, too) without to re-write them everywhere they are needed and without to be bound to external scripts invocation.

The way I think we can solve the problem refers to three interesting features available in bash:

• export functions from scripts (through export -f)
• execute scripts in the current shell’s environment, through source command
• execute scripts when bash starts

So I wrote the following script (say functional-bricks.sh):

and added the following line at the end of my user’s ~/.bashrc file:

and… voila!: now map and reduce implemented in functional-bricks.sh are available in all my bash sessions - so I can use them in all my scripts!
And because seeing is beleiving… if I launch the script use-functional-bricks.shdefined above, I get the following output: