css border corner joint and cut
css border property seems easy to use. “border:1px solid red;” will draw a border of 1-pixel thick solid red color around a block. But think a little further, you may […]
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cURL error 60: SSL certificate problem: certificate has expired
WordPress has a function download_url that can download a file(such as an image) from remote site. I got this “cURL error 60: SSL certificate problem: certificate has expired” error when […]
serialize vs json_encode, unserialize vs json_decode
You may have noticed the strange strings in WordPress’ wp_options table(in some option_value) like this: a:3:{i:0;i:123;s:3:”abc”;i:456;i:789;s:3:”def”;} It seems you can decipher it but it is not very easy to read. […]
Difference between print_r and var_dump
Both var_dump and print_r can print php variables in detail. What is the difference between print_r and var_dump? print_r displays less information than var_dump, thus more concise. print_r only shows […]
php SimpleXMLElement tutorial
Php has a SimpleXMLElement class to parse xml document. The official website gives quite a few examples on how to use it, but no explanation of related concepts. xml has […]
form without action
Html elements are so easy to learn. Even you are not major in computer science, even you are not a programmer, you can easily master them and use them to […]
Default flag for preg_match_all
The flag parameter of preg_match_all is complicated and confusing. The official document says the default value of flag is 0, which is wrong. In fact, the flag parameter is defaulted […]
php upload file
You might think it is a hard work to upload a file. At the client side, do I need to write code to open the file, read its content, then […]
How to replace all occurrences of a word with another word in all files in multiple directories and their sub-directories using bash?
I have a need to replace all email addresses of form admin@xxxx.com or admin@yyy.net or admin@zzzzz.org with root@localhost in all files under several folders and all their sub-folders. How can […]
How to strip the last n characters from a string in Bash?
How to remove the last several characters of a string? I have not considered this problem until recently. It turns out there are quite a few methods to delete the […]