Hi, there! The size of a filled named pipe is always zero. This is wrong! A read operation is going to hang for try to read from an empty pipe. To go around this trap it is necessary to do a conditional test on the filesize, [ -s pipe ]. Problem: The test doesn't work, because filesize is always zero. Try: mknod pipe & sleep 3600 <>pipe & echo 'date' >pipe [ -s pipe ] && echo "filled up" ls -l pipe; stat pipe # if size zero, it is wrong [ -s pipe ] && (read val <pipe; echo $val) This is a critical error. While parallel processing a script would be blocked. In worst case it causes a deadlock situation. Every changing of a condition of a file should be reported whithin the i-node. I found it in several disto: Ubuntu KarmicKoala 9.1, LucidLynx 10.04, Linux Mint Debian Edition 5, Slackware 13.1 x64 Best regards TOM
Not a bug - its the correct behaviour as per spec.