How can I use perldoc to lookup the %ENV variable?

StackOverflow https://stackoverflow.com/questions/84506

  •  01-07-2019
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Question

I find from reading perldoc perlvar, about a thousand lines in is help for %ENV. Is there a way to find that from the command line directly?

On my Windows machine, I've tried the following

perldoc ENV
perldoc %ENV
perldoc %%ENV
perldoc -r ENV (returns info about Use Env)
perldoc -r %ENV
perldoc -r %%%ENV
perldoc -r %%%%ENV (says No documentation found for "%ENV")

None actually return information about the %ENV variable.

How do I use perldoc to find out about %ENV, if I don't want to have to eye-grep through thousands of line?

I've tried the suggested "perldoc perlvar" and then typing /%ENV, but nothing happens. 

perl -v: This is perl, v5.8.0 built for MSWin32-x86-multi-thread

Though I've asked about %ENV, this also applies to any general term, so knowing that %ENV is in perlvar for this one example won't help me next time when I don't know which section.

Is there a way to get perldoc to dump everything (ugh) and I can grep the output?

Was it helpful?

Solution

perldoc doesn't have an option to search for a particular entry in perlvar (like -f does for perlfunc). General searching is dependent on your pager (specified in the PAGER environment variable). Personally, I like "less." You can get less for windows from the GnuWin32 project.

OTHER TIPS

Check out the latest development version of Pod::Perldoc. I submitted a patch which lets you do this:

$ perldoc -v '%ENV'

%ENV
$ENV{expr}
The hash %ENV contains your current environment. Setting a value in
"ENV" changes the environment for any child processes you subsequently
fork() off.

The searching for %ENV is a feature of the pager named 'less', not of perldoc. So if perldoc uses a different pager, this might not work.

Activestate Perl comes with HTML documentation, you can open perlvar in your browser, hit Ctrl+f and type %ENV, then hit enter.

I use Apache::Perldoc (old, but still does its job) on my local machine to browse the local documentation. If I have net access though, I just look at perldoc.perl.org and search. However, in this case, search isn't useful for the variables and it's better to use the Special variables link at the left of the page.

As you get more experience with Perl, you'll know where to look for the documentation. For know, you might have to refer to perltoc, but after awhile you'll know to look for functions in perlfunc, variables in perlvar, and so on.

You might also use my Perl documentation documentation.

firefox http://perldoc.perl.org/perlvar.html#%ENV

By the way, many many many bugs have been fixed since 5.8.0.

  1. Install unixutils for Windows
  2. Call: perldoc perlvar | grep -A10 %env

If you'd like to see the contents of your %ENV, you can use Data::Dumper to print it out in a rather readable format:

perl -MData::Dumper -e 'print Dumper \%ENV'

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