system/cal doesn't highlight current date.

chrisdee

Anybody know why the php system command doesn't highlight the current date when I run the unix/linux cal command?
When running the same command in unix/linux commandline the current date is highlighted.

<?php
echo "<pre>";
echo $output = escapeshellcmd(system("cal"));
echo "</pre>";
?>

sneakyimp

Firstly, you should not be using [man]escapeshellcmd[/man] on the output of [man]system[/man] -- all this does is escape the return value of whatever system returns (which is just a string representing the last line of output that results from your command). The point is to use escapeshellcmd on the command you supply to system().

I prefer to use [man]exec[/man] because it gives you more specific control over where the command result goes and its output goes and where the last line goes.

I tried this:

$command_output = NULL;
$return_value = NULL;
$last_line_of_output = exec("cal", $command_output, $return_value);

var_dump($command_output);
echo "\n=====\n";
var_dump($return_value);
echo "\n=====\n";
var_dump($last_line_of_output);

The output is interesting:

 array(8) {
  [0]=>
  string(14) "      May 2015"
  [1]=>
  string(20) "Su Mo Tu We Th Fr Sa"
  [2]=>
  string(20) "                1  2"
  [3]=>
  string(20) " 3  4  5  6  7  8  9"
  [4]=>
  string(20) "10 11 12 13 14 15 16"
  [5]=>
  string(20) "17 18 19 20 21 22 23"
  [6]=>
  string(24) "24 25 26 27 28 29 30"
  [7]=>
  string(2) "31"
}

=====
int(0)

=====
string(2) "31"

Note that the line with today's date ($command_output[6]) is four characters longer than the other lines which appear to have the same number of characters. My guess is that there are some non-printing characters included in the $command_output that you might be able to replace with some chars meaningful in your html.

sneakyimp

I just altered my script to get some additional interesting output:

$command_output = NULL;
$return_value = NULL;
$last_line_of_output = exec("cal", $command_output, $return_value);


//echo "\n=====\n";
$cal = implode("\n", $command_output);
//echo "\n=====\n";

for($i=0; $i<strlen($cal); $i++) {
  echo $i . ": " . $cal[$i] . " (ord: " . ord($cal[$i]) . ")\n";
}

In the output, these lines in particular are of interest:

126: 2 (ord: 50)
127: 6 (ord: 54)
128:   (ord: 32)
129: _ (ord: 95)
130: (ord: 8)
131: 2 (ord: 50)
132: _ (ord: 95)
133: (ord: 8)
134: 7 (ord: 55)
135:   (ord: 32)
136: 2 (ord: 50)
137: 8 (ord: 56)

You can see that after 26, we have asci chars 32, 95, and 8 before the "2" in 27 (today's date). You also have the 95 and 8 after that "2" and then 32 following the "7" in 27. I'm not really sure what these chars mean but expect they are meaningful to a terminal window as some kind of formatting command. Consulting an ASCII chart, I see that ASCII chars 0-32 are "non-printing chars"
ASCII 8 - backspace
ASCII 32 - substitute
* ASCII 95 - underscore (i.e., "_")

I'm not sure at all, but it looks like the ASCII 32 starts and ends the altered formatting around today's date ("27") and that ASCII 95 ASCII 8 precede the affected chars. Beyond that I'm not really sure what to do with this information.

Weedpacket

ASCII 32 is a space; SUB ("substitute") is 26. what happens is that an underscore is typed on the console (ASCII 95), then the cursor is moved back (ASCII 8), and a digit (ASCII 50, or 55) typed over that.

HTML of course does not work that way.

sneakyimp

Weedpacket;11047925 wrote:
ASCII 32 is a space; SUB ("substitute") is 26. what happens is that an underscore is typed on the console (ASCII 95), then the cursor is moved back (ASCII 8), and a digit (ASCII 50, or 55) typed over that.

Oops. Sorry about mistake on ASCII code. So ASCII 32 is probably not meaningful.

Weedpacket;11047925 wrote:
HTML of course does not work that way.

It does not, but there might be some way to reverse-engineer the 'markup' or whatever.

Seems to me each bold/reversed char is preceded by ASCII 95 and then ASCII 8. One might be able to use regex or iterate through the chars returned to concoct a solution. Like this perhaps:

<?php
$command_output = NULL;
$return_value = NULL;
$last_line_of_output = exec("cal", $command_output, $return_value);


//echo "\n=====\n";
$cal = implode("\n", $command_output);
//echo "\n=====\n";

$pattern = "/([^_]*)((" . preg_quote(chr(95) . chr(8)) . "\d+)+)+([^_]*)/";
$matches=NULL;
$match_count = preg_match_all($pattern, $cal, $matches);
echo $match_count . " matches found\n";
var_dump($matches);


//echo $cal . "\n";

echo $matches[1][0] . "<b>" . $matches[2][0] . "</b>" . $matches[4][0] . "\n";

?>