Shell Programming and Scripting

So Scott, you are saying that if "." is not mentioned in my PATH variable then ./MyScript give me the desired results?

else simply executing MyScript will do. Is it?

Code:

./MyScript

... will explicitly execute MyScript in the current directory

Code:

MyScript

... will execute the first executable program (or script) called MyScript in your PATH.

Code:

$ mkdir T1 T2

$ echo "echo T1_script" > T1/Script

$ echo "echo T2_script" > T2/Script

$ PATH=T1

$ chmod u+x T1/Script T2/Script
-ksh: chmod: not found        chmod is not in my path any more

$ /bin/chmod u+x T1/Script T2/Script

$ Script
T1_Script

$ PATH=T2

$ Script
T2_Script

Also, "." should never be in your PATH anyway.

This prevents a situation where someone can put a file named, for example, "ls" in their own home directory, which contains commands only root can execute, and have you unknowingly execute it as root (by simply typing "ls").

So, you should always be referencing your scripts with either ./ or full path.

Don't necessarily agree with that! For example, if you create a script called test.ksh in your current directory, having '.' as the very first element of $PATH means that invoking test.ksh will use that instead of any other one that may be lying around elsewhere in your PATH, so for me, it's useful.
Depending on your operating system and shell, you can invoke these commands to determine which one will actually run...

Code:

> whence test.ksh
/home/jerry/test.ksh

Code:

>type test.ksh
test.ksh is /home/jerry/test.ksh

Code:

>which test.ksh
./test.ksh

sh script.ksh runs the script even if it is not in executable mode