Archive for 'Linux Utilities'

Using exec-shield to protect your Linux servers from stack, heap and integer overflows

I’ve been a long time follower of the OpenBSD project, and their amazing work on detecting and protecting the kernel and applications from stack and heap overflows. Several of the concepts that were developed by the OpenBSD team were made available in Linux, and came by way of the exec-shield project. Of the many useful […]

Fcron, a feature rich cron and anacron replacement

I’ve been looking at some opensource scheduling packages, and while doing my research I came across the fcron package. Fcron is a replacement for vixie cron and anacron, and provides a number of super useful features: – Run jobs based on the system load average. – Serialize jobs. – Set the nice value of the […]

Configuring wget to use a proxy server

Periodically I need to download files on servers that aren’t directly connected to the Internet. If the server has wget installed I will usually execute it passing it the URL of the resource I want to retrieve: $ wget prefetch.net/iso.dvd If the system resides behind a proxy server the http_proxy variable needs to be set […]

Four super cool utilities that are part of the psmisc package

There are a ton of packages available for the various Linux distributions. Some of these packages aren’t as well know as others, though they contain some crazy awesome utilities. One package that fits into this cataegory is psmisc. Psmisc contains several tools that be used to print process statistics, look at file descriptor activity, see […]

Figuring out how long a Linux process has been alive

I’ve bumped into a few problems in the past where processes that were supposed to be short lived encountered an issue and never died. Over time these processes would build up and if it wasn’t for a cleanup task I developed the process table would have eventually filled up (the bug that caused this was […]

Dealing with xauth “error in locking authority file” errors

I recently logged into one of my servers and received the following error: $ ssh foo matty@foo’s password: Last login: Tue Nov 1 13:42:52 2011 from 10.10.56.100 /usr/bin/xauth: error in locking authority file /home/matty/.Xauthority I haven’t seen this one before, but based on previous “locking issues” I’ve encountered in the past I ran strace against […]

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