Remote Desktop replacement

At work I have 5 Linux machines (1 desktop and 4 tiny embedded machines) and a Windows laptop in my office which I need to use.  There are KVM switches which would allow to connect my monitor, keyboard, and mouse to the machines in that large a setup but they're expensive and the cabling would be a nightmare plus I'd be stuck using just one machine at a time.  I tried using Remote Desktop and VNC to access the desktop of another machine remotely but that's cumbersome and it's slow across a VPN.  To be fair, there are situations when Microsoft's Remote Desktop works wonderfully across a VPN.  At my last job I used to use the Mac version of Remote Desktop to access my Windows laptop at work.  Since a Windows machine was the destination, Remote Desktop did a great job of data compression plus it allowed the client machine to arrange windows differently than they were arranged on my Windows laptop at the office.  So my old 27" iMac which has nearly 4k resolution gave me a better viewing setup than I had at work.

Now I use X11 (aka X-Windows) for accessing all the Linux machines I need access to.  Making this work requires a couple pieces of software.

First off, I need an X Server on my Windows laptop.  That is used to display the windows created by the remote Linux machine.  I use VcXsrv, a version of the classic xorg X Server but recompiled under Visual C++.  This recompilation allows it better access to Windows resources and I find it works better than any other X Server I've tried such as xming or cygwin's xwin.  VcXsrv needs to be run on your Windows machine prior to attempting a connection to another machine.

The next thing required is an SSH client which is capable of X11 forwarding.  That allows any programs launched using the SSH client to send their displays back to the client machine.  I use PuTTY, which has been around a long time and which can handle serial and SSH connections.

Once you've run VcXsrv on your Windows machine and then used PuTTY to connect to a Linux machine (taking care to first set the configuration to allow X11 forwarding), launching a remote program and having it display on your client machine is as simple as typing the program's name.  As an example you can try xterm which will create an X11 terminal window.  Just be sure to launch it in the background by appending an ampersand so the program is placed in the background.  Otherwise, your input and output will remain tied up by the program being launched.  The command to launch xterm this way would be "xterm &".

Favorite books

Since I love to read, people sometimes ask me about my favorite books.  I inevitably leave some out so I thought I'd collect them in an easy-to-find place.  So here are my favorites.

Favorite authors still actively publishing
Connelly, Michael - Harry Bosch series
Crais, Robert - Elvis Cole/Joe Pike series
Doctorow, Cory - Little Brother, Walkaway, Makers, and others
Gaiman, Neil - American Gods and anything else
Hiaasen, Carl - anything
Ide, Joe - IQ series
Kowal, Mary Robinette - anything
Scalzi, John - anything
Sloan, Robin - Mr. Penumbra's 24-Hour Bookstore and others
Stross, Charles - the Laundry File series
Taylor, Dennis E - Bobiverse series
Wells, Martha - Murderbot series


Other favorite books (sorted by author name):
Adams, Douglas - First two Hitchhiker's Guide books and Dirk Gently series
Asimov, Isaac - Robot series, Foundation trilogy
Dudley, John Ball - In the Heat of the Night
Ellison, Harlan - Dangerous Visions and others
Feynman, Richard - Surely You're Joking, Mr. Feynman!: Adventures of a Curious Character
Follett, Ken - Eye of the Needle
Goldman, William - The Princess Bride & The Marathon Man
Heinlein, Robert A. - The Moon is a Harsh Mistress and his juvenile series
Irving, John - A Prayer for Owen Meany
Kidder, Tracy - The Soul of a New Machine
Kipling, Rudyard - Kim, Captains Courageous, and others
Leonard, Elmore - Maximum Bob
London, Jack - anything
Miller, Walter M - A Cantical for Leibowitz
Niven, Larry - Ringworld
Noah, Trevor - Born a Crime: Stories From a South African Childhood
Parker, Robert B. - early Spenser novels, Jesse Stone series, Virgil Cole/Everett Hitch series
Pullman, Philip - His Dark Materials trilogy
Robinson, Spider - Callahan's Crosstime Saloon series
Sayers, Dorothy - Lord Peter Wimsey series
Shute, Nevil - Trustee from the Toolroom
Sturgeon, Theodore - More Than Human and all others
Tolkien, J.R.R. - The Lord of the Rings trilogy
Twain, Mark - anything
Vonnegut, Kurt - Slaughterhouse Five and all others
Weir, Andy - The Martian
Winters, Ben H - The Last Policeman trilogy
Wodehouse, P.G. - Meet Mr. Mulliner and others

Favorite graphic novels (sorted by author name):
Ennis, Garth - Preacher, The Boys
Moore, Alan - Watchmen, V for Vendetta
O'Malley, Bryan Lee - Scott Pilgrim's Precious Little Life
Vaughn, Brian K. - Ex Machina

GNU Screen can make SSH sessions persistent

 I do a fair number of Linux kernel builds at work.  Doing a Yocto build for our target machine takes about an hour and 40 minutes for a the build to complete and the root filesystem to be prepared.  If I do that from home, there's a chance that I'll get a hiccup on my VPN connection which might disrupt the build in progress.  Even at work, I ssh into my Linux build machine from a Windows laptop and use xterm sessions for most of my development tasks.  If I kick off a build before heading home, there's always a chance that Windows will decide to do an update which could also disrupt my build.

Fortunately GNU Screen can make your sessions persistent through disruptions due to network disconnections or other reasons.  Now I make sure to start a GNU Screen session before doing my build.  I start named screen sessions with a command such as "screen -S build".  That way, if my session is disconnected, I can rejoin it with the command "screen -r build".

The one thing I don't like about GNU Screen is its default escape key, Control-A, since that interferes with the default Emacs command line editing mode in Bash.  So I've created a ~/.screenrc configuration file with the following command to change the escape key to Control-T.

escape ^tt

Running Ubuntu Linux in a VirtualBox VM

I've recently started a new job which requires me to build software under Ubuntu Linux.  Since I don't particularly care for the Ubuntu distribution and having only a single development PC which runs Windows 10, the natural solution is to create a VirtualBox virtual machine and install Ubuntu in that.  However the combination of VirtualBox and Ubuntu caused a few problems for me.

The first problem I encountered is that VirtualBox seems determined that new VMs will all run at very low resolutions.  I've seen 640x480 being used on when running VirtualBox on both Macs and PCs running Windows 10 and it's ridiculous to be stuck with a resolution that first appeared in 1987.  At that resolution, it's difficult to get through the Ubuntu installation setup as some of the buttons appear off the screen.  That issue I believe is Ubuntu's fault.  They should make it possible to see all buttons regardless of screen resolution.  Poking around on Google, I discovered that there's a command line utility included with VirtualBox which allows you to run higher resolutions in the guest OS in VMs.  First make sure that VirtualBox is not running.  Start a command prompt with administrative privileges and navigate to the directory where VirtualBox is installed since the utility we need is not located in the command path.  The directory you want will most likely be something like "C:\Program Files\Oracle\VirtualBox".  Issue the command "VBoxManage setextradata global GUI/MaxGuestResolution any".  This plus installed the Guest Additions tools in the guest OS should allow you to change your VM to a higher resolution.

The second problem I encountered was after I installed the GUI version of my favorite editor, Vim, using the command "sudo apt install vim-gnome".  I was able to launch gvim but the menu was hidden which makes accessing a few features more difficult than necessary.  It turns out Gnome on Ubuntu has a bug which prevents some applications from displaying a menu bar.  The workaround is to define a command alias to launch Vim which undefines the UBUNTU_MENUPROXY variable.

Vi/Vim macros

Of all the editors I've used (and there have been a lot) I like Vi/Vim the most.  Once you get past the very steep learning curve, you can become extremely productive, in part because you almost never need the mouse.  I've been using Vi on and off since 1990 which has imprinted the commands into my fingers so I no longer think about them.  A few of the macros below have existed in some form since that time.

The macro commands below are from the _vimrc file I use to customize Vim under Cygwin running on Windows 10.  Note that characters in red below indicate control characters.  ^M is control-M which is the code produced by the Enter key on Windows keyboards.  ^[ is the code produced by the Escape key.

One of the things which saves time for me is having the ability to easily copy and paste lines from one file being edited to another.  These macros help me accomplish that.

" set temporary yank and paste filename
let @p="c:\\Users\\ViUser\\Documents\\vim\\vim.tmp"

" mark beginning of a line block (uses the a mark)
map \m ma

" yank lines to temp file (from mark to cursor pos. - uses b mark, b buffer)

map \Y :'a,.w! p^Mmb"ay'a`b

" paste lines previously yanked or deleted to temp file at cursor pos.

map \P k:r p^M

Another thing I do frequently is edit log files and search for my initials which I include in any log messages I add.  The macro below searches the log file being edited for the letters "TBD" and removes all other text.  Just remember to quit without saving or use the Vim undo command.

map \gt ^[ggVG!grep TBD^M

Customizing the bash prompt

I prefer to use a bash prompt which displays both the date and time.  That makes it easier to see when commands were issued when scrolling back through the terminal's buffer.  Here's what my prompt looks like.

The bash settings for this prompt are shown below.  You can add these lines to your .bashrc file.  For operating systems which support an admin or root user, I change the prompt's background from blue to red to give quick confirmation of that elevated privilege level.

# Attribute codes:
# 00=none 01=bold 04=underscore 05=blink 07=reverse 08=concealed
# Text color codes:
# 30=black 31=red 32=green 33=yellow 34=blue 35=magenta 36=cyan 37=white
# Background color codes:
# 40=black 41=red 42=green 43=yellow 44=blue 45=magenta 46=cyan 47=white
PBG=44
PFG=37
TFG=36

PS1='\n\[\e]1;Term ${$} \a\e]2;\u@\h - ${PWD}\a\e[1;${PFG};${PBG}m\][\D{%m-%d} \t] eh? \[\e[m\] '

Searching for source files which contain multiple keywords

Recently I was presented with the challenge of searching for the code which built a SQL query.  I knew what the query looked like from a log file but searching for individual terms used in the query such as SELECT, FROM, or WHERE produced hundreds of matches which I didn't want to waste time checking one at a time.

So I created the following bash script to search files for each term in order.  I used ack instead of grep for the first search so it would pick only source files of interest for me.  The results from my bash script returned only a single file which contained all the terms and it was this one which I needed to modify.

if [ -z "$2" ]                       # Is parameter #1 zero length?
then
    echo "usage -- rgt term1 term2 [term3]..."
    exit 1
fi

files=`ack -l "$1"`

# shift past the first search term argument since 
# we've already used that one 
shift  

for var in "$@"
do
    files=`echo $files | xargs grep -l $var`
done

if [ -z "$files" ]; then    # are results zero length?
    echo "no matching files found"
else
    echo "matching files:"
    echo "-------------------------------------"
    echo "$files"
fi