get environment variables of a process with ps - 2: the win!

Yeah, I got it!

First the solution, some comment right afterwards:

#!/usr/bin/perl -w

$catch = shift @ARGV;
while (<>) {
    /(.*?) ([A-Z|_]*?=.* )+$catch=(\S*?) /;
    print $1." ".$catch."=".$3."\n";
}

Things was more confusing with sed due to the fact that it pretends to work with the /pattern/substitution/ pair. Now I simply parse my line capturing what I'm interested in, and then using only it to make the output.

The interpretation is now straight forward:

• take the first part of the string until the first group of capital letters or underscore followed by an equal sign; this will be the normal output for each process, and this will be printed out;
• not be greedy looking for the equal sign, and take the firs you encounter (the ? after the *) so that this will match a single pair VAR=value; but then let this pairs be more than one (the + just after the second parentheses group);
• then you will find a particular pair, which starts with the first argument i gave you ($catch)

Let's say that this perl script is named select.pl, you can pipe it after you ps call just my previous alias... but now it's parametric:

ps -ely --forest | grep myscript.pl | select.pl PWD

ps -ely --forest | grep myscript.pl | select.pl PATH

ps -ely --forest | grep myscript.pl | select.pl LOGIN

And if you now can't live without the --color feature of grep, perl can emulate it for you using the Term::ANSIColor module:

#!/usr/bin/perl -w

use Term::ANSIColor;

$catch = shift @ARGV;
while (<>) {
    /(.*?) ([A-Z|_]*?=.* )+$catch=(\S*?) /;
    print $1." ";
    print color("red bold"), $catch, color("reset");
    print "=".$3."\n";
}

Please enjoy!