Shell Programming and Scripting

Hi. I am new to shell scripting.
I am writing a simple sequential logic script. After completing the script, the instructions say "use the sh command instead of the chmod comand".
Why didn't I have to use "chmod ugo+x scriptname",& then type ./ scriptname or just scriptname after using chmod?
Thanks In Advance
P.S. mmmmmmm...I did put my working directory in the environmental var. PATH. I think I'm getting confused.

script can be executed in lot number of ways ...

if you change the permission to executable mode and if its executed .. it may run the current shell (i.e $SHELL) else ... in the first line of the script you might have given #!/bin/ksh which will execute the commands in that shell(over here ksh)..

if you prefix like sh ,commands will be executed in that shell.

if you are not clear .. i request you to clearly mention your questions ..

If you use

Code:

sh script

then the script does not have to be executable so a chmod is not necessary (I think they want this so that the script runs with sh and not what you happen to put in the shebang)

Thank you everyone for your answers. They were informative and very helpful.
A Grateful,
ccccc