How to execute shell command and echo multiple lines from PHP?

Question

Re,

I use a shell command cat to dump multiple lines into a file like so:

cat > file <<CHAR
one
two
three
CHAR

Here's my problem: I need to execute the same cat command using shell_exec in PHP. How would I dump the contents of an array and terminate the command with CHAR? I know this sounds odd but I need to create a file using sudo and I don't want to dump everything into a temporary file and then sudo cp it to the intended location.

Thanks.

hek2mgl · Accepted Answer · 2013-08-09 01:05:36Z

1

Do it like this:

shell_exec('cat > file <<EOF
foo
bar
EOF
');

Of course this will only work if the underlying shell supports the here-doc syntax.

answered Aug 9, 2013 at 1:05

hek2mgl

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3 Comments

MarkL Over a year ago

Thanks. I had to implode my array using PHP_EOL to make it work.

MarkL Over a year ago

Your join with \n won't work as it will produce a single-line file with line breaks not being recognized. That's why I used PHP_EOL

hek2mgl Over a year ago

I've tested this code. you need double quotes if you need escape sequences: "\n".

PleaseStand · Accepted Answer · 2013-08-09 01:15:36Z

1

Use popen() instead of shell_exec():

$filename = 'file';
$text = 'CHAR
one
two
three
';

$cmdline = 'cat > ' . escapeshellarg($filename);
$fp = popen('sudo /bin/sh -c ' . escapeshellarg($cmdline), 'w');
fwrite($fp, $text);
pclose($fp);

answered Aug 9, 2013 at 1:15

PleaseStand

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1 Comment

MarkL Over a year ago

popen is an interesting alternative. thanks, I will read up on it!

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