You have some home made scripts or programs sitting in your home directory but you always need supply a full path to those scripts in order to be able to execute them. This is fine for a short time but in the long run this can be quite tedious and thus ineffective. The problem is that the path to your scripts is not defined by bash PATH environmental variable. To add path to your scripts pernamently even after reboot modify your ~/.bash_profile file. For example to add paths:
~/bin and ~/android-sdk
add a following line to your ~/.bash_profile file.
To make the above line affective you need to log out or reboot your system.