Passing Arrays between PHP and Bash
Bash provides one-dimensional array variables that you declare using the form:
Array_name=(value1 ... valuen).
You can then reference any element of an array using the syntax
${name[subscript]}. There is no maximum limit on the size of an array. For example, you can pass a set of arguments to a Bash script that groups them into arrays. The following PHP script (
array.php) sends a list of integers:
<?php
$result=shell_exec(
"C:\bash-2.03\bash.exe array.txt 10 2 13 88 76 34");
echo($result);
?>
The
arrayNumber.txt Bash script in
Listing 1 extracts the arguments and creates two Bash arrays (the Bash script also provides a few basic array operations):
The code in
Listing 1 stores output into an
arrayNumberResult.txt file. When you run the example, the output is:
First numeric array is: 10 2 13
Second numeric array is: 88 76 34
Length of first array is: 3
Length of second array is: 3
0 ----> sum[0] = myArray1[0] + myArray2[0] *** 98
product[0] = myArray1[0] * myArray2[0] *** 880
average[0] = (myArray1[0] + myArray2[0])/2 *** 49
------------
1 ----> sum[1] = myArray1[1] + myArray2[1] *** 78
product[1] = myArray1[1] * myArray2[1] *** 152
average[1] = (myArray1[1] + myArray2[1])/2 *** 39
------------
2 ----> sum[2] = myArray1[2] + myArray2[2] *** 47
product[2] = myArray1[2] * myArray2[2] *** 442
average[2] = (myArray1[2] + myArray2[2])/2 *** 23
------------
The sum of all elements of the first array is *** 25
------------
The first array after deleting the second element is *** 10 13
------------
Listing 2 contains a similar example that uses string arrays and demonstrates operations over strings (add, paste, display length, and so on). The PHP script (
array.php) that runs the Bash script is:
<?php
$result=shell_exec(
"C:\bash-2.03\bash.exe array.txt red black white blue pink");
echo($result);
?>
When you run
array.php script, the result stored in the
arrayResult.txt file is:
Length of first array is 2
Length of second array is 3
------------
red <--> white
red <--> blue
red <--> pink
black <--> white
black <--> blue
black <--> pink
------------
red
black
aqua
magenta
------------
redwhite
blackblue
aquapink
magenta
------------
Passing True PHP Arrays
If you want to pass a PHP array to Bash instead of a list of arguments, convert the PHP array into a string and pass it as shown below (you can use any element separator you like):
<?php
$nr = array("one", "two", "three", "four", "five");
$separated = implode(":", $nr);
echo 'The PHP array converted in a string: <br />';
echo $separated."<br /> <br />";
$result=shell_exec("C:\bash\bash-2.03\bash.exe arrayToBash.txt '".$separated."'");
…
Next, the Bash script will build an array from this string as follows:
#!/bin/bash
string=$1
until [ "$token" = "$string" ]
do
token=${string%%:*}
a[$i]=$token"BASH"
string=${string#*:}
((i=i+1))
done
#echo "a[0]="${a[0]}
#echo "a[1]="${a[1]}
#echo "a[2]="${a[2]}
#echo "a[3]="${a[3]}
#echo "a[4]="${a[4]}
echo ${a[@]}
PHP may reconstruct the array from the Bash string using code like this:
//convert from Bash string to PHP array
$pieces = explode(" ", $result);
echo "<br /><br /> Convert from Bash string to PHP array: <br />";
echo "pieces[0]=".$pieces[0]." <br />";
echo "pieces[1]=".$pieces[1]." <br />";
echo "pieces[2]=".$pieces[2]." <br />";
echo "pieces[3]=".$pieces[3]." <br />";
echo "pieces[4]=".$pieces[4]." <br />";
?>
The output is (notice that Bash script added the "BASH" text termination for every array element—this is just a flag to show that the Bash script worked):
The PHP array converted in a string:
one:two:three:four:five
The Bash array elements:
oneBASH twoBASH threeBASH fourBASH fiveBASH
Convert from Bash string to PHP array:
pieces[0]=oneBASH
pieces[1]=twoBASH
pieces[2]=threeBASH
pieces[3]=fourBASH
pieces[4]=fiveBASH
Passing PHP objects to Bash
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