What is the difference executing a script with . in the front versus not putting a "."


 
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# 1  
Old 04-07-2010
What is the difference executing a script with . in the front versus not putting a "."

Hi All,
I know this has been discussed a lot but still I need some more answers. I am running this is ksh on AIX 5.3

I believe putting a "." in front of the script will start a new shell, is that correct??

I have a script which override some PATH variables and it does not do that unless I use a . in the front?

Like . .profile

Any idea why??Smilie
# 2  
Old 04-07-2010
Yes.
It is called "sourcing". The script runs in the context of the existing process, rather than in a child process. bash and some other envrionments provide the command "source" which does the same thing as well.

This allows any envrionment variable defined in .profile to become part of the calling process envrionment.
# 3  
Old 04-07-2010
Thanks Jim
# 4  
Old 04-07-2010
somescript:
Code:
A=1
echo somescript $$ $A

Next ex. start new process in line somescript and after child has ended, we return pack to the our main process. Child set own variable A, it's not same as mother's A.
Code:
A=2
echo "$$ $A"
somescript
echo $A

In this example somescript is "included" to the this script = same process, same variables, ....
I have said
. = is include and execute, easy to understand
Code:
A=2
echo "$$ $A"
. somescript
echo $A

So if you run your profile like
.profile
you create child process, give some values for child and process end.

But
. .profile
you run .profile in your process, so you change/add variables and so on.
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