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   1  # Run a command with an environment defined by another command.
   2  
   3  use warnings;
   4  use strict;
   5  use Getopt::Long;
   6  use Pod::Usage;
   7  
   8  # Your usual option-processing sludge.
   9  my %opts;
  10  GetOptions (\%opts, 'help', 'no-error')
  11      or pod2usage (2);
  12  
  13  (exists $opts{'help'})
  14      and pod2usage ('-exitstatus' => 0, -verbose => 2);
  15  
  16  # Ensure exactly two arguments
  17  scalar @ARGV == 2
  18      or pod2usage (2);
  19  
  20  my ($env_cmd, $cmd) = @ARGV;
  21  
  22  my @settings = `$env_cmd`;
  23  
  24  $opts{'no-error'} || $? == 0
  25      or die "$env_cmd failed, status ", $? / 256, '.', $? %256;
  26  
  27  # Update environment with settings.
  28  foreach my $setting (@settings) {
  29      chomp $setting;
  30      my ($var, $value) = $setting =~ /^([^=]+)=(.*)\z/;
  31      defined $var
  32          or die "Unable to parse output of $env_cmd:\n  $setting\n  ";
  33      $ENV{$var} = $value;
  34  }
  35  
  36  # Run "real" command.
  37  
  38  system $cmd;
  39  $? == 0
  40      or die "$cmd failed, status ", $? / 256, '.', $? %256;
  41  
  42  exit 0;
  43  
  44  __END__
  45  
  46  =head1 NAME
  47  
  48  with-env.pl - Use one command to set another's environment
  49  
  50  =head1 SYNOPSIS
  51  
  52  with-env.pl [ options ] <env_cmd> <cmd>
  53  
  54  Options (may be abbreviated):
  55  
  56   --help         Display this help and exit
  57   --no-error     Do not abort if <env_cmd> gives an error
  58  
  59  =head1 DESCRIPTION
  60  
  61  This script takes two arguments, which are both commands to be run.
  62  The first command should output one or more lines of the form:
  63  
  64    VARIABLE=VALUE
  65  
  66  (Note that there is no space around the equals sign.)  This script
  67  will add these settings to the environment, and then run the second
  68  command.