note 17523 deleted from function.exec by jimw
| From: | jimw@php.net | Date: | Thu, 20 Dec 2001 23:45:59 +0000 |
| Subject: | note 17523 deleted from function.exec by jimw | ||
| References: | 1 | Groups: | php.notes |
| Request: | Send a blank email to php-notes+get-23592@lists.php.net to get a copy of this message | ||
Getting exec() command results into the related array
(Watch out for HEX 0A 00)
I had a need to use exec to grab the results of a command that would normally go to stdout.
So I first try a simple command like "ping", this works fine as below, showing each line
of the ping command.
// This works fine
$command = "ping -c5 localhost";
exec ($command, $results);
$maxidx = count ($results);
for ($idx = 0; $idx < $maxidx; ++$idx) {
echo ("Line $idx contains: $results[$idx] <BR>\n");
}
Now, I want grab the contents of a plain text file into the array. The below command does not work
as expected, it results in one blank (null) array member for each line of text. A 100 line text file
gets you 100 blank array items. The same is true of the file("somefile.txt") command.
// This get you an array of nulls
$command = "cat somefile.txt";
exec ($command, $results);
$maxidx = count ($results);
for ($idx = 0; $idx < $maxidx; ++$idx) {
echo ("Line $idx contains: $results[$idx] <BR>\n");
}
So I checked the hex values of the plain text file. Turns out that each line starts with HEX 0A 00,
a line feed and a null. This can be seen by doing "cat -A somefile.txt". It is
understandable that the exec() array loading routine sees HEX 0A 00 and gets a blank line, certainly
not what I want or expected.
Knowing this quirk, I can then deal with it. Turn those non-printable HEX characters into printable
ones I can control and work around. This works:
// This get you an array of text, each line starting with ^@ ending with $
$command = "cat -A somefile.txt";
exec ($command, $results);
$maxidx = count ($results);
for ($idx = 0; $idx < $maxidx; ++$idx) {
echo ("Line $idx contains: $results[$idx] <BR>\n");
}
Sure would be nice to be able to control the way exec() loads the array with a hex switch or
something.