What is the purpose of the PATH variable?

I'm more or less a total newbie myself but I am trying to use one so that I can run an executable from anywhere, a bit like how you might use gcc to compile something.

I am sure someone else can give a better, more thorough explanation though :-)

When you issue a command to run an application, the system sequentially searches the directories specified in the PATH variable.

For example: If your PATH var contains '/usr/bin:/usr/local/bin:/bin and issue the command to run the test.sh script, the system would look for the test.sh script first in /usr/bin, then /usr/local/bin and finally /bin.

If runs the first instance of the file found. If after searching the directories specified in your PATH var, it does not find a test.sh file it issues the 'command not found' error message.

However, if your specify an absolute path for test.sh, it ignores all of the above and looks directly in the directory specified for the file. So entering:
would cause the system to look directly in /usr/bin for the test.sh file.

To run the test.sh script from the present working directory, use:

Unless you have made some modifications to your system then this is not true under Linux/Unix. The current directory is not searched, often leading to confusion for people new to Linux/Unix.

My mistake, you're correct. Not on my p's and q's.

Thank you for your responses that helps!!!