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Old 07-24-2005, 12:37 PM   #1
calutateo
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Registered: May 2004
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set or env?


Hi,

The commands set and env both deliver the environment variables and their values, however
Code:
set | wc -l
769
env | wc -l
81
What ist the difference between them?
Could somebody name a good tutorial with examples?

Regards, Carsten
 
Old 07-24-2005, 12:55 PM   #2
avarus
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Hi Carsten,

The difference is that 'set' is also reporting shell-local variables. These look the same from the point of view of the shell user, but are not passed on to the new process if you run a command. When you use the 'export' command you promote a shell variable to be an environment variable.

Environment variables are a fundametal feature of Linux, while shell variables are just a feature of the shell. To fully understand how environment variables work you really need to appreciate the fork/exec process model. I would direct you to the mighty Rute for some explanation:

http://www.icon.co.za/~psheer/book/node12.html.gz

TIM
 
Old 07-24-2005, 01:56 PM   #3
calutateo
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Tim,

Thank you very much for the excellent explanation. And thank you also for the Rute link. I read the Rute book more than 4 years ago, and I completely forgot about it. Great book.

Regards, Carsten
 
  


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