http://qs321.pair.com?node_id=33658


in reply to RE (tilly) 1: Get default login environment
in thread Get default login environment

And that two-level map is probably crazier than you need: 
return $env =~ /^(.*?)=(.*)/gm;

[download]
Create fewer intermediate SVs and regex calls that way.

-- Randal L. Schwartz, Perl hacker

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RE (tilly) 3: Get default login environment
by tilly (Archbishop) on Sep 22, 2000 at 21:37 UTC
    Actually...try this on for size: 
    sub get_login_env {
  local %ENV;
  my $shell = shift || (getpwuid($<))[8];
  my $env = `echo env | perl -e 'exec {"$shell"} -sh'`;
  if (wantarray) {
    my @pieces = ($env =~ m/^(.*?)=((?:[^\n\\]|\\.|\\\n)*)/gm);
    s/\\(.)/$1/g foreach @pieces;
    return @pieces;
  }
  else {
    return $env;
  }
}

    [download]
    Doesn't that take care of everything about how the env function encodes the environment? I tried putting = and returns into the name of environment variables and it wouldn't go...

    EDIT
    I edited the RE slightly. I also should note that compared to the effort of launching a Perl process that execs itself into a login shell, a few invocations of the RE engine are unlikely to do much further damage...

    UPDATE (Much later), Corion caught a silly missing | in the line that gets the environment. :-(

    UPDATE 2 (Years later), as the discussion below points out, there was a silly syntax error. Fixed. Believe it or not, I used a version of this snippet for years, but that copy had been typed separately...

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[d/l]
      I downloaded this code but it doesn't work! When I try and use it the following error occurs - 
      syntax error at xxrcprofsub.pl line 8, near "m/^(.*?)=((?:[^\n\\]|\\.|
+\\\n)*)/gm
;"

      [download]
      The code to call this sub is also in a format that, novice that I am, I've not seen before - 
      %ENV = (%ENV, get_bash_login_env());

      [download]
      The ENV inside the brackets is throwing me. Is this the means by which the local (in the subroutine) %ENV is used to overwrite the existing %ENV? I've not seen this syntax before. Ronnie Cruickshank
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[d/l]
[select]

        It was missing a closing bracket just before the ";" in that line. This works:

        sub get_login_env {
  local %ENV;
  my $shell = shift || (getpwuid($<))[8];
  my $env = `echo env | perl -e 'exec {"$shell"} -sh'`;
  if (wantarray) {
    my @pieces = ($env =~ m/^(.*?)=((?:[^\n\\]|\\.|\\\n)*)/gm );
    s/\\(.)/$1/g foreach @pieces;
    return @pieces;
  }
  else {
    return $env;
  }
}

        [download]

        Cheers, Sören

[reply]
[d/l]
      Thanks, that's a great help. Bye, Ron.
[reply]
Re^2: RE (tilly) 1: Get default login environment
by ronbarak (Novice) on Oct 03, 2006 at 12:23 UTC
    Thanks, Mr. Schwartz: that's a great shortcut. (Wow, an answer from the person who's book is on my shelf :-) Bye, Ron.
[reply]

In Section Cool Uses for Perl