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Old 02-21-2010, 08:59 AM   #1
spampig
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Simple Question? The 'DOT' in a shell script test


I was looking at this line in an init file:

Code:
test -f /etc/default/postfix && . /etc/default/postfix
Which I understand to mean test that files /etc/default/postfix AND etc/default/postfix exist. Two things crossed my mind.

First, There was no action associated with the line at all - so regardless of the result of the test, it appears to be superfluous - unless....

I noted the period/dot just after the && and I don't honestly know what it means in this context.

Google would be the first port of call, but searching for '.' is notorious. The best I could find was 'run in the same shell' but I can't make the connection in my brain of where this fits in to the context of the test.

Can anyone put me out of my misery?
 
Old 02-21-2010, 09:01 AM   #2
macemoneta
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The statement reads, if /etc/default/postfix exists, then source /etc/default/postfix.

The '.' means source the file. That is, make the contents of the file part of the current environment.

Usually the file will contain functions and/or variables that are set.

Last edited by macemoneta; 02-21-2010 at 09:02 AM.
 
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Old 02-21-2010, 09:45 AM   #3
spampig
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I never knew that! You've given me a much needed pointer to find out more. Really appreciate it - thanks for your time and response.
 
  


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