Linux

The OpenSSH secure shell, ssh, provides the necessary client/server security plumbing, to allow shell execution on a remote machine. ssh can be used interactively, as per a normal shell, or to run one off commands, for example: $ ssh ben@wookie.local uname -a ben@wookie.local's password: Linux wookie.local 3.14-1-686-pae #1 SMP Debian 3.14.7-1 (2014-06-16) i686 GNU/Linux Hot tip: the w command is gem for showing users currently logged in $ w -f USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT ben tty2 :0 17:05 10:36m 16:53 50.97s /usr/bin/evince /home/ben/podcasts/redhat/Docs/RH124-RHEL7.pdf User ben logged into virtual console 2 (tty2) via a graphical login (:0) at about 5PM. OK, lets access a couple of the virtual terminals: ...

Here I aim to cover a set of common administration tasks. Things like, the hostname, system logs, what users are currently logged in, physical devices that are connected, logical volumes, file system and inode allocation, attached network interfaces and their addressing, processes and daemons currently running, kernel verison, local users and groups, installed packages, remote mounts, network shares, system uptime, bread and butter OS stats (CPU, IO, network, memory). Booting shutdown -r +5 System going down for a reboot #wall broadcast msg shutdown -c #cancel reboot shutdown -r 00:00 #schedule for midnight shutdown -h +5 #halt system in 5 mins shutdown -h now Alternatively, just use systemd: ...

I run Debian on a ThinkPad T420s. ThinkPad’s have a great Linux compatibility story, and the T420s is no exception. The cooling fan situation seemed in need of some attention though, with fans running at high RPM most of the time. Not only was this really noisy, hit the battery quite hard too. Enter thinkfan, a simple fan control program. Works with any linux hwmon driver, especially with thinkpad_acpi. It is designed to eat as little CPU power as possible. ...

After recently getting my hands dirty with the wonderful [sed]({% post_url 2015-09-15-sed %}), the time has come for me to step it up with awk. Incepted in 1977 at Bell Labs, AWK is an interpreted programming language designed for text processing, and is a defacto part of most nix based distributions. The original version of UNIX awk was designed and implemented by Alfred Aho, Peter Weinberger, and Brian Kernighan (notice the first letter of their surnames together) of Bell Laboratories. Brian Kernighan continues to maintain and enhance it. Paul Rubin and Jay Fenlason, of the Free Software Foundation, wrote gawk, to be compatible with the original version of awk distributed in Seventh Edition UNIX. ...