I had to enable virtualization technologies in my BIOS. I have a Lenovo T520 and did this by pressing F1 during startup and then going to Security > Virtualization. If I did not do this then I would receive the error “VT-x features locked or unavailable in MSR” when trying to run with more than 1 CPU or 3584 MB of RAM.

Also, I had to run “sudo apt-get install dkms” to get the VirtualBox Guest Additions to work well.

Finally, I remapped the host key. By default all kinds of weird things happen when you use the right Ctrl button. This can be fixed by going to File > Preferences… > Input and then setting Host Key to something you never use like Pause.

Sed regex reminders:

• You need a backslash before parens in a regex grouping
• You refer to matched regex groups using \1, \2, etc.
• The + regex operator does not work
• Non-greedy quantifiers don’t work.  For example, .*? will not work
• The output is printed to standard out by default.  You need the -i option if you want to edit a file with sed.

Remove all but the first column in a .tsv stream
sed ‘s/\([^\t]*\).*/\1/’

Edit a .tsv file by removing all but the first column
sed -i ‘s/\([^\t]*\).*/\1/’

Remove the first line of a stream
sed ’1d’

Strip trailing whitespace from a file
sed -i -e ‘s/ *$//’

Replace @inheritDoc with @override after marking for edit
grep @inheritDoc -l -r java/com/benmccann | xargs p4 edit
grep @inheritDoc -l -r java/com/benmccann | xargs sed -i ‘s/\(.*\)@inheritDoc/\1@override/’

Replace @inheritDoc with @override in JS files after marking for edit
find java/com/benmccann -name ‘*.js’ -print0 | xargs -0 grep -l @inheritDoc | xargs p4 edit
find java/com/benmccann -name ‘*.js’ -print0 | xargs -0 grep -l @inheritDoc | xargs sed -i ‘s/\(.*\)@inheritDoc/\1@override/’

java -Xdebug -Xrunjdwp:transport=dt_socket,address=8000,server=y,suspend=y -jar myProgram.jar

The program will wait for you to attach the Eclipse debugger to it. Open Eclipse and choose:

Run > Debug Configurations... > Remote Java Application > New

Make sure to enter the same port that you chose on the command line. The default is port 8000. Now hit “Debug” and you’re off!

sudo apt-get install apache2 libapache2-mod-php5 php5-mysql
sudo /etc/init.d/apache2 restart

Download SQL Buddy, unzip, and move to /var/www

$ mysql -u XXXXX -pXXXXX db_name

CREATE USER 'user1'@'localhost' IDENTIFIED BY 'pass1';
GRANT ALL ON *.* TO 'user1'@'localhost';
CREATE USER 'user1'@'%' IDENTIFIED BY 'pass1';
GRANT ALL ON *.* TO 'user1'@'%';

select host, user, password, Create_priv from mysql.user;

show databases;
show tables;

ALTER TABLE Article change article_id id bigint(20);

ALTER TABLE Person MODIFY firstName varchar(255) NOT NULL;

ALTER TABLE Person ADD UNIQUE INDEX(memberId);

SELECT table_schema "DB Name", sum(data_length + index_length) / 1024 / 1024  "DB size in MB" FROM information_schema.TABLES GROUP BY table_schema;

gpg --list-keys

If you didn’t and need to create a key then run:

gpg --gen-key

It might hang for awhile while generating enough random entropy. Run “ls -R /” to speed things up.

And upload it to a public key server:

gpg --keyserver hkp://pgp.mit.edu --send-keys <keyid>

Now list the keys again to get the keyid:

gpg --list-keys

The keyid is the half after the / in:

pub   XXXX/XXXXXXXX 2011-12-05

Then generate your key:

gpg -ab <filename>

If you’re doing this for an upload to the Maven repositories, you’ll need to do this for each of the four file (.jar, -sources.jar, -javadoc.jar, and .pom) and then jar all eight files together in a bundle.jar file.  More details available on Maven’s how to generate PGP signatures page.

I was unable to resume my NX session.  While trying to connect, the resume button was greyed out (or grayed out)  This apparently can happen if the two machines are running at a different color depth.

The machine I was trying to connect to was running Ubuntu, so I checked the color depth (sudo cat /etc/X11/xorg.conf) and saw that it was running at 24 bit.  Then I checked the color depth on my Windows machine (Control Panel > Display > Settings > Color Quality) and saw it was running at 16 bit.  There was no option to set it to 24-bit, so I chose the option “Highest (32 bit)”.  No more disabled resume button!

I think the cause of the problem was plugging my laptop into the projector at work yesterday.  It apparently changed my color depth and Windows didn’t reset it when I exited presentation mode.

Execution of last command failed

Trying to reconnect to my NX session kept failing.  I hit the Details button and saw the following:

NX> 596 NX> 596 ERROR: NXNODE Ver. 3.4.0-6  (Error id e76DC5C)
NX> 596 NX> 596 ERROR: resume session: run commands
NX> 596 NX> 596 ERROR: execution of last command failed
NX> 596 NX> 596 last command: '/bin/kill -USR2 16905'
NX> 596 NX> 596 exit value: 1
NX> 596 NX> 596 stdout:
NX> 596 NX> 596 stderr: /bin/kill: 16905: No such process

The only thing I found that would let me connect to my box via NX at all was to “rm /usr/NX/var/db/running/*” in order to kill my current session.  Killing the session is a sucky option, but at least now I can use NX again.

new Exception().printStackTrace();

If you want more control over the output, you can build some code off the following:

  System.out.println("Printing stack trace:");
  StackTraceElement[] elements = Thread.currentThread().getStackTrace();
  for (int i = 1; i < elements.length; i++) {
    StackTraceElement s = elements[i];
    System.out.println("\tat " + s.getClassName() + "." + s.getMethodName()
        + "(" + s.getFileName() + ":" + s.getLineNumber() + ")");
  }

lsof -i -n -P | grep :80

alias ll='ls -la'           # list all directory contents in listing format
alias untargz="tar zxvf"    # unpacks a .tar.gz file
alias rd='cd `pwd -P`'      # change to the real directory if in a linked directory

• sudo lshw -html > hardware.html – Creates an HTML page showing what hardware is on your system
  
• uname -mr – Shows what kernel version and processor you are running on
• df and fdisk -l – Gives you file system info.  Can help you figure out how things are mounted

• dmesg – Useful for tracking down problems during boot
• tail -f /var/log/messages – Now run the process giving you problems and you might see helpful error messages

• top – Shows the programs which are the top memory and CPU users
• free -m – Shows how much memory is free. Linux uses 100% memory by default so as to not waste memory by letting it sit empty. Look at the buffers/cache line to see how much is really used.
• pgrep - Returns the process ids of a given program, allowing you to kill frozen programs

• scp -i key.pem local_file user@remote_machine:remote_path – Securely transfers a file

• find – Find a file on the file sytem
• sed – Programmatically edit a file or stream

If you’ve got other suggestions, please feel free to comment below.  Thanks!