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Using the Linux alternatives command to manage multiple Arduino IDE versions

Submitted by gill on

The Arduino package contains an IDE that can be used to develop and upload code to the micro-controller.

  • Install from the repositories:

    sudo yum -y install arduino

    Run the Arduino IDE and set your preferences, etc. and test that it works. Your user may need to be added to some groups (dialout and lock in Fedora 20) to have permissions to write to the serial interface on your computer.

    Optionally, install the alternatives graphical user interface. You can use this interface to switch between your options rather than using the command.

    • Fixed clamav logging error

    Submitted by gill on

    service clamd start
    Starting Clam AntiVirus Daemon: ERROR: Can't open /var/log/clamav/clamav.log in append mode (check permissions!).
    ERROR: Can't initialize the internal logger
    [FAILED]

    # grep clam /etc/selinux/targeted/contexts/files/file_contexts

    /var/log/clamav.* system_u:object_r:antivirus_log_t:s0

    # semanage fcontext -a -t antivirus_log_t "/var/log/clamav(/.*)?"
    # restorecon -R /var/log/clamav
    # chown clam:clam /var/log/clamav *log

    Installing Sun Java with Fedora/RedHat alternatives

    Submitted by gill on

    Download java:
    http://java.com/en/download/linux_manual.jsp?locale=en
    Install with rpm:
    rpm -Uvh jre-7u67-linux-x64.rpm
    Set alternatives:
    update-alternatives --install "/usr/bin/java" "java" "/usr/java/latest/bin/java" 1 \
    --slave "/usr/bin/keytool" "keytool" "/usr/java/latest/jre/bin/keytool" \
    --slave "/usr/bin/unpack200" "unpack200" "/usr/java/latest/bin/unpack200" \
    --slave "/usr/bin/pack200" "pack200" "/usr/java/latest/bin/pack200" \
    --slave "/usr/bin/rmid" "rmid" "/usr/java/latest/bin/rmid" \

    Fastest DNS

    Submitted by gill on

    Ran some tests and found these DNS entries for my router are faster:

  • 24.93.41.125
  • 209.18.47.62

    • However, they are managed by TimeWarner, and are not very reliable.
    So, maybe I go back to OpenDNS

  • 208.67.222.222
  • 208.67.220.220

    • or
    Google DNS

  • 8.8.8.8
  • 8.8.4.4

    • BeagleBone Black setup - lapdock

    Submitted by gill on

    Setup the BeagleBone Black with Motorola Atrix Lapdock
    Make a backup first; edit /boot/uboot/uEnv.txt
    Comment out optargs, then add a line:

    ## Graphics for Altrix
    optargs=quiet drm.debug=7 capemgr.disable_partno=BB-BONELT-HDMI video=HDMI-A-1:1360x768M@60

    Edit /etc/X11/xorg.conf (make a backup first)

    Section "Module"
    Load "extmod"
    Load "dbe"
    Load "glx"
    Load "freetype"
    Load "type1"
    Load "record"
    Load "dri"

    BeagleBone Black setup - wireless

    Submitted by gill on

    Run lsusb and make sure the dongle is registered.

    Bus 001 Device 005: ID 0bda:8176 Realtek Semiconductor Corp. RTL8188CUS 802.11n WLAN Adapter

    Create /etc/wpa_supplicant/wpa_supplicant.conf

    ctrl_interface=/var/run/wpa_supplicant
    # WPA network
    network={
    ssid="fishred"
    psk="thepassphrase"
    priority=1
    }
    # WPA network
    network={
    ssid="fishblue"
    psk="thepassphrase"
    priority=1
    }

    Edit /etc/network/interfaces

    New webcam server

    Submitted by gill on

    Zoneminder was running, and it does the job fine. But the server kept crashing. So I'm installing something simpler, after replacing the OS.
    CentOS 6.5
    Get epel, rpmforge repos
    Install Apache, php
    yum install ffmpeg
    Run ffserver

    GNOME 3 Nautilus sorting order

    Submitted by gill on

    I can't find the preferences menu for Nautilus in GNOME 3. But gsettings works.
    To set the default sort order:

    gsettings set org.gnome.nautilus.preferences default-sort-order name

    To show the directories first, before the files:

    gsettings set org.gnome.nautilus.preferences sort-directories-first true

    It works :-)

    Install IBM Java on Fedora

    Submitted by gill on

    First, download the IBM Java SDK from http://www.ibm.com/developerworks/java/jdk/linux/download.html
    Install java (by running ibm-java-sdk-7.1-0.0-x86_64-archive.bin as root) into /usr/lib/java/ibm-java-x86_64-71.
    Change the alternatives links by running:

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