Simple shell scripting question: set name of directory using variable?

Question

Here's a very simple, probably duplicate (sorry - I have tried searching) shell scripting question.

What's the correct syntax to set DATA_DIR as a subdirectory of WDM_DIR, in the script below? (Line 2.)

WDM_DIR='/Users/ap257/wdm/wdm'
DATA_DIR=$WDM_DIR+/wdm/pylons_data/getdata/
cd $DATA_DIR

The point is that people can change WDM_DIR to whatever path is right for their system, but DATA_DIR is always in the same place relative to it.

Answer 1

The easy way is:

DATA_DIR="${WDM_DIR}/wdm/pylons_data/getdata/"

Answer 2

Here is the correct syntax

WDM_DIR=/Users/ap257/wdm/wdm
DATA_DIR=${WDM_DIR}/wdm/pylons_data/getdata/
cd -- "$DATA_DIR"

Well the syntax may vary a bit depending on what shell you are using.