Programming Course - Environment Variables (1)

Environment variables

UNIX system environment variables hold your 'preferences' at run time.
To get the list of your current environment, enter 'env' on the UNIX command line.

The %ENV hash

Every perl script has access to a 'Global Special Array' named %ENV, containing the current environment.
For example,

print "$ENV{'PATH'}\n"; # shows the default value for PATH

$ENV{'PATH'} = "/usr/bin:usr/local/bin"; # sets the value for PATH
$ENV{'PATH'} .= "/usr/bin:usr/local/bin"; # appends to your current PATH

Watch your environment

Useful environment variables when accessing external web pages include:


$ENV{'http_proxy'} = "http://wwwproxy.weizmann.ac.il:8080/";
$ENV{'no_proxy'} = "ac.il";

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