Month: December 2015

Cat Links BASH, Linux

Include $HOME/bin in the path for bash shell

Posted on stamatis

Say we want to have our $HOME/bin added to the $PATH First check that the PATH does not already contain our $HOME/bin, by issuing in a terminal: echo $PATH If our $HOME/bin is contained in the $PATH we need to do nothing further, otherwise, proceed as follows: If you haven’t yet, create the directory bin in your home: mkdir bin Edit $HOME/.bashrc and add the following towards the end of the file: [[ -d $HOME/bin ]] && \ [[ ! $PATH =~ $HOME/bin ]] && \ PATH=$HOME/bin:$PATH && \ export PATH Edit $HOME/.profile or $HOME/.bash_profile and do the same. Log out of the system and log back in and check the path in a terminal: echo $PATH We should now find that the $HOME/bin is included in our $PATH, whether bash is used as a login shell or just as a terminal Also note that the [[ ! $PATH =~ $HOME/bin ]] condition prevents the $HOME/bin to appear more than once in our $PATH

Cat Links Firefox

Firefox JavaScript settings

Posted on stamatis

In newer versions of Firefox, the javascript options to allow (or not) scripts to perform certain operations on the browser are accessible through about:config Prevent javascript from moving or resizing windows: dom.disable_window_move_resize true: block script, false: allow script Prevent javascript to raise or lower windows: dom.disable_window_flip true: block script, false: allow script Permit javascript to disable context menu (mouse right-click): dom.event.contextmenu.enabled false: block script, true: allow script

Cat Links Linux, System

Properly run chroot in a hosted system

Posted on stamatis

Say we want to chroot into a different environment residing under /mnt/testEnv which could either be a mounted filesystem or just a directory structure Run: mount -t proc proc /mnt/testEnv/proc Next: mount -o bind /dev /mnt/testEnv/dev Next: mount -t sysfs sys /mnt/testEnv/sys Next: mount -t devpts pts /mnt/testEnv/dev/pts Finally: chroot /mnt/testEnv

Cat Links Linux, SUDO

SUDO extra functionality in /etc/sudoers.d/

Posted on stamatis

Say our username is mike and our host is alpha To add specific commands (say /bin/binary1 and /bin/binary2) that we would be able to run through sudo without a password, we can do the following: Run sudo visudo -f /etc/sudoers.d/mike and add the following to it: mike alpha=(root:root) NOPASSWD: /bin/binary1,/bin/binary2

Cat Links Solaris

Solstice Disk Suite / Solaris Volume Manager

Posted on stamatis

Create State Database (3 database replicas on 4 slices (12 state replicas): metadb -a -f -c 3 c0t1d2s3 1 c1t2d3s4 c2t3d4s5 c3t4d5c6 Create 1 concatenated volume from 4 slices: metainit dxx 4 1 c0t1d2s3 1 c1t2d3s4 1 c2t3d4s5 c3t4d5c6 Create 2 striped volumes from 3 slices with 32k interleave: metainit dxx 2 3 c0t1d2s3 c1t2d3s4 c2t3d4s5 -i 32k Create 2 striped volumes from 3 slices: metainit dxx 2 3 c0t1d2s3 c1t2d3s4 c2t3d4s5 Create a RAID 5 volume from 4 slices: metainit dxx -r c0t1d2s3 c1t2d3s4 c2t3d4s5 c3t4d5s6

Cat Links Linux, Terminal

Linux Serial Terminal (Hard-wired Host To Host)

Posted on stamatis

Say we have a host alpha and a host bravo that is connected to alpha with serial cable. The following entries are required within /etc/inittab of the host alpha (to make the configuration permanent): T0:23:respawn:/sbin/getty -L ttyS0 115200 vt100 Next, re-read the /etc/inittab of host alpha by running: init q From host bravo, connect with: cu -l ttyS0 -e -o -115200

Cat Links Linux, X11

Quick keyboard layout setting

Posted on stamatis

Say you want to use an additional layout on your keyboard in a terminal, to support Hellenic (gr) along with your English (gb) layout, and also want to be able to switch layouts with <Shift> + <CapsLock> and have the [Scroll Lock] LED light up when the second layout is active In your terminal or console session, run setxkbmap -option grp:switch,grp:shift_caps_toggle,grp_led:scroll gb,gr

Cat Links Linux, X11

X Terminal setup with XDM

Posted on stamatis

The XClient / XServer model, is in a nutshell described as follows: XServer: Is the host that will display the session (also called X-Terminal). Only requires the X11 system to be installed and optionally a display manager (no desktop or window manager are necessary). The Xserver can be invoked by a number of ways: From the command line as root, run: “X :1 -query xclientHost” In the /etc/X11/xdm/Xservers add the following: “:1 local /usr/X11R6/bin/X :1 -query xclient-host” XClient: Is the host that will export its display to the XServer (X-Terminal). Requires a desktop / window manager and optionally a display manager. The following files need modification as follows: /etc/X11/xdm/Xaccess: *.your-domain.ext *.your-domain.ext CHOOSER BROADCAST /etc/X11/xdm/xdm-config: !DisplayManager.requestPort: 0 /etc/X11/xdm/Xservers: #:0 local /usr/X11/bin/X :0 vt9 -depth 15 -nolisten tcp

Cat Links Linux, X11

Configure language switching on keyboard

Posted on stamatis

Say we want to add the Hellenic (el) keyboard layout in X11. Edit /etc/X11/xorg.conf and add the following entries Option “XkbLayout” “gb,el” # British, Hellenic Option “XkbOptions” “grp:alt_shift_toggle” # Switch with Alt-Shift Log out / in your X session and try out the configuration by pressing <Alt>+<Shift>

Cat Links Linux, SUDO

SUDO installation and configuration

Posted on stamatis

Install the sudo package using your system’s package manager (Gdebi, synaptic, aptitude, apt-get, yum, rpm, or whichever package manager is available on your system) In a terminal (which we’ll refer to as root terminal from now on), run su to log in as root, and then run: egrep -e ‘sudo|wheel’ /etc/group to determine if group sudo or wheel (or even both) exist on your system If the output is like: sudo:x:27: we can go ahead and add ourselves to it by running in the root terminal: usermod -a -G sudo your_username In the root terminal run visudo and locate the %sudo or %wheel references and make sure that the one that refers to the group you’ve added yourself to is uncommented, e.g. %sudo ALL=(ALL:ALL) ALL Log out of your desktop manager and log back in to activate the group membership you have just added yourself to. In a normal terminal, run sudo su – root and put your own password once asked. If all has gone to plan you should be presented with the root prompt. In another terminal, run gksu-properties and select sudo for Authentication mode and ensure Grab mode is set to enabled and press Close