使用PHP以编程方式查找wget位置？

Question

Is it possible to determine where the wget binary is located using PHP? I'm trying to create a softcoded wget cron command for my users. I know that in most environments, the wget location will already be included in the PATH but cron doesn't always share the same environment. To play it safe, I want to use an absolute path like /usr/bin/wget .

Is there a constant similar to PHP_BINDIR ? I cannot assume wget will be in the same location as PHP, right? Any other ideas?

Thanks for any help!

Answer 1

That's why we have env , which is guaranteed to be in /usr/bin , so all you have to do is:

/usr/bin/env wget [options] [url]

And you're good to go, provided the user running the PHP script has the correct permissions to execute wget , write the downloaded files to the specified path etc... but that's a different matter

On the other hand, because you've tagged this question with the crontab tag, make sure the hashbang at the top of your script uses env , too:

#!/usr/bin/env php
<?php
//your script here

Then, wget will be callable (again: if the environment variables, and permissions check out) plain and simple:

#!/usr/bin/env php
<?php
exec('wget --help', $output);
var_dump($output);

Should yield zomething like:

array(172) {
  [0]=>
  string(51) "GNU Wget 1.15, a non-interactive network retriever."
  [1]=>
  string(32) "Usage: wget [OPTION]... [URL]..."
  [2]=>
  string(0) ""
  [3]=>
  string(72) "Mandatory arguments to long options are mandatory for short options too."
  ...

Tried it on my machine, no problems whatsoever

Answer 2

Is not a php command, but a unix command : which .

Example :

~ $ which wget
/usr/bin/wget