regex - PHP and preg_replace -

i have text parsing this:

some text. text. text. text. text. text. text. text. text. text. text. text. text. text. text. text. text. [attachment=0]winter.jpg[/attachment]some text. text. text. text. text. text. text. text. text. text. text. text.

i want match , remove instance of text string:

[attachment=0]winter.jpg[/attachment] 

where winter.jpg can text.

however, getting php notices. used regexpal.com construct this, works there uses javascript regex function:

\[attachment=.*?].*\[/attachment] 

when run code:

$pm_row['message_text'] = preg_replace('\[attachment=.*?\].*\[/attachment\]', '', $pm_row['message_text']); 

php complains notice:

[phpbb debug] php notice: in file /mail_digests.php on line 841: preg_replace() [function.preg-replace]: delimiter must not alphanumeric or backslash 

so on similar line of code, delimit pattern "/":

$post_row['post_text'] = preg_replace('/\[attachment=.*?].*\[/attachment]/', '', $post_row['post_text']); 

but generates following:

[phpbb debug] php notice: in file /mail_digests.php on line 957: preg_replace() [function.preg-replace]: unknown modifier 'a' 

any ideas how fix this?

you need escape every occurrence of delimiter inside pattern:

if delimiter needs matched inside pattern must escaped using backslash. if delimiter appears inside pattern, idea choose delimiter in order increase readability.

so escape it:

'/\[attachment=.*?].*\[\/attachment]/'                        ^ 

by way: quantifier in .* greedy, means match as possible. might want change ungreedy variant using ? did before.