topic Re: Unbuffered pipes in Operating System - Linux

Unbuffered pipes

Thomas Boerner_1 — Wed, 25 Jul 2001 10:03:12 GMT

Hi all,

this is probably an easy one but I didn't figure it out yet: How do I make a pipe unbuffered? I get output normally only after a page (4k) is full or when the pipe is closed. But I need it immediately. My case: starting a ppp connection from script and checking success; or grepping lines from /var/log/messages and sending to different application.

Thx for your help in advance
Thomas

Re: Unbuffered pipes

Vincent Fleming — Tue, 31 Jul 2001 01:12:27 GMT

I use "tail +0f" to do this. It's line-buffered, which is appropriate for watching a log file or command output live.

For example:

# tail +0f /var/log/messages

You could pipe to it as well:

# my_ppp_command 2>&1 | tail +0f

which would gather both stdout and stderr, and show you a line every time one was printed out.

Give it a try. Good luck!