A while back I wrote a blog entry showing how to get tape drives statistics with systemtap. This script wasn’t very reliable and I would frequently see it crash after collecting just a few samples. Due to the work of some amazing Linux kernel engineers I no longer have to touch systemtap. Recent Linux kernels […]
Archive for 'Linux Utilities'
I think humor plays a big role in life, especially the life of a SysAdmin. This weekend I was cleaning up some sudoers files and came across a reference to the “insult” option in the documentation. Here is what the manual says: “insults If set, sudo will insult users when they enter an incorrect password. […]
Linux has a guadzillion debugging utilities available. One of my favorite tools for debugging problems is strace, which allows you to observe the system calls a process is making in realtime. Strace also has a “-c” option to summarize system call activity: $ strace -c -p 28009 Process 28009 attached Process 28009 detached % time […]
After many years of use it’s become almost second nature to type ‘telnet <HOST> <PORT>’ when I need to see if a system has TCP port <PORT> open. Newer systems no longer install telnet by default: $ telnet google.com 80 -bash: telnet: command not found I can’t think of a valid reason to keep telnet […]
Software fails, and it often occurs at the wrong time. When failures occur I want to understand why, and will usually start putting together the events that lead up to the issue. Some application issues can be root caused by reviewing logs, but catastrophic crashes will often require the admin to sit down with gdb […]
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 […]