Learning about the Buffer Gate.
So I found out about stdbuf. To get it:
# apt-get install coreutils
If you want your ssh client to use line-buffered streams use -t -t.
So I ended up with:
# su -c "stdbuf -oL ssh -t -t /usr/bin/tail -f /var/input.log | stdbuf -oL tr -c '\\11\\12\\15\\40-\\176" myuser \ | tee -a /tmp/input.log \ | grep --line-buffered -v "...ignore..." \ >> /tmp/output.log
Holy command-line Batman!
I was configuring MediaWiki to allow uploads and was getting an error in the browser about the POST data being too large (“does not allow request data with POST requests, or the amount of data provided in the request exceeds the capacity limit.”). I had a look in the Apache error log and found:
[Thu Feb 23 16:12:45 2012] [error] [client 220.127.116.11] request body exceeds m aximum size (131072) for SSL buffer, referer: https://www.jj5.net/morpheus/Speci al:Upload [Thu Feb 23 16:12:45 2012] [error] [client 18.104.22.168] could not buffer messa ge body to allow SSL renegotiation to proceed, referer: https://www.jj5.net/morp heus/Special:Upload
So I did some research. I found this document, File upload size which suggested editing /etc/php5/apache2/php.ini which I did:
upload_max_filesize = 20M post_max_size = 80M
Eventually I found Bug 491763 – HTTPS+SSLVerifyClient require in <Directory>+big POST = Apache error which suggested I needed to apply the SSLRenegBufferSize directive which I did like this:
<Location /morpheus> SSLVerifyClient require SSLVerifyDepth 1 SSLRenegBufferSize 20971520 </Location>
And then after restarting Apache the problem was solved.
There’s a function in PHP called readfile which will read a file and send its contents to stdout. That can be handy, but it’s not much good to you if you want to read the content of the file into a string.
There’s a neat trick using PHP’s output buffering that enables you to read the content of a file into a string without printing anything on stdout, and it goes like this:
// start an output buffer ob_start(); // print the file to the output buffer readfile( $file_path ); // get the contents of the output buffer $content = ob_get_contents(); // cancel the output buffer ob_end_clean();