Chad's Blog

Month: May 2015

  • Run a Program in the Background with nohup on Ubuntu Gnome 15.04

    This is post is how to run a program from the terminal in the background so that it will continue to run even when the terminal window is closed. I use the nohup command to accomplish this. I have a server that I log into with ssh. I run a rysnc backup command to that copies data to a usb3, 2 GB external hard drive.  This can take several hours to complete. Sometimes I need to close my ssh session, for example to reboot my client computer, yet I don’t want the backup to stop. I am running linux, Ubuntu Gnome 15.04 and all commands are run from the terminal.

    Example of no hup command

    nohup nice -n20 bkup.offsite.cc.com.py > /dev/null 2>&1 &

    I will break down what is happening.

    nohup – prevents the commands following from stopping if the terminal window is closed

    nice -n20 – runs the program bkup.offsite.cc.com.py at a lower priority for cpu resources to prevent other programs on the computer from slowing down

    bkup.offsite.cc.com.py – the python backup program to execute

    > /dev/null 2>&1 – This does not show error messages and output, nohup normally writes standard output to a file nohup.txt. When my output was written to nohup.txt, the file size was 1.2 GB!

    & – puts the command in the background so that you can use the terminal for other tasks

    To see the status of your running application run the following command:

    jobs

    Output will be:

    [1]+  Running   nohup nice -n20 bkup.offsite.cc.com.py &

    A good reference for working with jobs: http://linuxcommand.org/lc3_lts0100.php

    Reference: http://unix.stackexchange.com/questions/32574/when-do-you-need-nohup-if-youre-already-forking-using?lq=1

  • Add Owncloud Clients to Iphone IOS and OSX Yosemite

    Iphone IOS

    Click on this link, http://itunes.apple.com/us/app/owncloud/id543672169?ls=1&mt=8, to open the owncloud client in the App Store. Download and instructions are here https://owncloud.com/products/mobileapps/.

    Mac Laptop or Desktop running OSX Yosemite

    Click on the following link to install the software https://owncloud.com/download#desktop-clients.

    Download and instructions here https://owncloud.com/products/desktop-clients/. “Simply copy a file into the directory and the ownCloud desktop client does the rest. Make a change to the files on one computer, it will flow across the others using these desktop sync clients. Always have your latest files with you wherever you are.”

     

  • How to See Information about a Installed Debian Package

    I needed to see what version of mythtv was installed on my Ubuntu 14.04 server and what dependencies it requires. Here is the solution.

    .deb packages are stored at /var/cache/apt/archives

    View mythtv package name

    #ls -l /var/cache/apt/archives/mythtv*
    mythtv_2%3a0.27.4+fixes.20150514.6b73976-0ubuntu0mythbuntu4_all.deb

    Display Package Version

    # apt-show-versions mythtv
    mythtv:all/trusty 2:0.27.4+fixes.20150514.6b73976-0ubuntu0mythbuntu4 uptodate

    Reference: http://unix.stackexchange.com/questions/6284/check-package-version-using-apt-get-aptitude

    Display Package Information

    #dpkg -I mythtv_2%3a0.27.4+fixes.20150514.6b73976-0ubuntu0mythbuntu4_all.deb

    new debian package, version 2.0.
    size 78060 bytes: control archive=1084 bytes.
    1449 bytes, 34 lines control
    209 bytes, 3 lines md5sums
    Package: mythtv
    Version: 2:0.27.4+fixes.20150514.6b73976-0ubuntu0mythbuntu4
    Architecture: all
    Maintainer: MythTV Ubuntu Maintainers <ubuntu-mythtv@lists.ubuntu.com>
    Installed-Size: 101
    Depends: mysql-server | mysql-server-5.6, mythtv-database, mythtv-frontend, mythtv-backend, ntp | time-daemon | ntp-simple
    Suggests: mythtv-doc
    Section: graphics
    Priority: optional
    Homepage: http://www.mythtv.org
    Description: Personal video recorder application (client and server)
    MythTV implements the following PVR features, and more, with a
    unified graphical interface:
    .
    - Basic 'live-tv' functionality. Pause/Fast Forward/Rewind "live" TV.
    - Video compression using RTjpeg or MPEG-4
    - Program listing retrieval using XMLTV
    - Themable, semi-transparent on-screen display
    - Electronic program guide
    - Scheduled recording of TV programs
    - Resolution of conflicts between scheduled recordings
    - Basic video editing
    .
    http://www.mythtv.org/
    .
    This package will install a complete MythTV client/server environment on a
    single system. If you are intended on using this as your only MythTV machine,
    and this machine is already configured as a desktop, this package will get you
    up and running switfly.
    .
    If you are intended on installing this on a standalone/non-desktop machine,
    you should look into the metapackages available:
    mythtv-backend-master (backend with a local database)
    mythtv-backend (backend needing a remote database)

    Reference: http://askubuntu.com/questions/80655/how-can-i-check-dependency-list-for-a-deb-package

    2015-05-14