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RE: RE (tilly) 1: Get default login environment

by merlyn (Sage)
on Sep 22, 2000 at 21:01 UTC ( [id://33658]=note: print w/replies, xml ) Need Help??

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;
Create fewer intermediate SVs and regex calls that way.

-- Randal L. Schwartz, Perl hacker

Replies are listed 'Best First'.
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; } }
    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...

    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...

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

        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; } }

        Cheers, Sören

      Thanks, that's a great help. Bye, Ron.
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.

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