Mika/Notes/Computer Stuff

Miscellaneous

Writing down things I've learned. Some miscellaneous stuff are:

• AJAX example: Checks if the username you entered is taken.
• Javascript example: Drag choices up and down.
• The tool to take a screen-videoshot (screencast) is to install recordmydesktop.
• i686 (or i386) are 32 bit. Intel 64 bit processor is usually marked by _64 (really?)
• Add a keyword (i.e. g) to a bookmark (i.e. http://www.google.com/search?q=%s) to make a shortcut in the address bar in Firfox.
• R tutorial
• Vector graphics vs Raster graphics
• To rid the high pitch noise on my X61s, add options processor max_cstate=2 to your /etc/modprobe.d/options file.
• In order to have certain things started every time I start my laptop, I can add things to the .Xsession file and start the session with Xsession when I log in. I've added things like gnome-power-management and awesome (awesome should be at the end).
• I installed chromium by following this instruction.
• Change network manager keyring by Applications > Accessories > Passwords and Encryption Keys.
• Firefox forgets history after 7 days even though it's set to remember for up to 90 days. I went about:config and changed browser.history_expire_days to 90 days.
• Converting 3gp to avi: I had to do sudo apt-get install ffmpeg libavcodec-extra-52 to get extra libraries. Then, a variation of ffmpeg -i input.3gp -f avi -vcodec xvid -acodec mp3 -ar 22050 output.avi because it gave errors for xvid (change to libxvid) and mp3 (change to libmp3lame). Still not working but it at least makes the output file.
• Things to check out: gcommons, bak, acabed
• In order to hide oversized background on a website, use in CSS: overflow:hidden;
• sh files --> sh file.sh
• imap folder can be merged by tagging all msgs in one folder and ;s (save) in the folder of my choice.
• tgz files: gzip -d filename
• baobao: graphical tool for space analysis
• ibus-daemon wasn't working. I couldn't start it by ctrl-space: 1) ps ax |grep ibus (this showed "defunct for ibus) 2) ps ax |grep X 3) restart X by killing

the process (That didn't fix it. See the next point.)

• upon Ubuntu Upgrade, the Japanese input stopped working ("no input window" in ibus). I uninstalled scim and it's all fixed now.
• smbclient -L (server name) to see the list of services on the server.
• Start mutt. c and imap://(server name) to get emails on the local machine.
• Thumbnail images for RAW files stopped working. Installed gnome-raw-thumbnailer (probably) again. Also created a file raw.thumbnail saying:

[Thumbnailer Entry]

Exec=/usr/bin/gnome-raw-thumbnailer -s %s %u %o MimeType=image/x-3fr;image/x-adobe-dng;image/x-arw;image/x-bay;image/x-canon-cr2;image/x-canon-crw;image/x-cap;image/x-cr2;image/x-crw;image/x-dcr;image/x-dcraw;image/x-dcs;image/x-dng;image/x-drf;image/x-eip;image/x-erf;image/x-fff;image/x-fuji-raf;image/x-iiq;image/x-k25;image/x-kdc;image/x-mef;image/x-minolta-mrw;image/x-mos;image/x-mrw;image/x-nef;image/x-nikon-nef;image/x-nrw;image/x-olympus-orf;image/x-orf;image/x-panasonic-raw;image/x-pef;image/x-pentax-pef;image/x-ptx;image/x-pxn;image/x-r3d;image/x-raf;image/x-raw;image/x-rw2;image/x-rwl;image/x-rwz;image/x-sigma-x3f;image/x-sony-arw;image/x-sony-sr2;image/x-sony-srf;image/x-sr2;image/x-srf;image/x-x3f;

• Iceweasel/Firefox keyword shortcuts: Right click on a search box (i.e. Duckduckgo search box) and select "Add keyword shortcut" and add a keyword.
• Piwik is like visitors. Used Piwik Analytics, a wordpress plugin. Make sure to insert / for the path to piwik.php etc and enter correct site ID obtained from the analytics code. I inserted the code from the Piwik server on other pages in index.html. Make sure that the text doesn't wrap in the middle of the code. In vim, :set textwidth=1000 etc.
• Accidentally changed the WP siteurl on the admin page to a wrong url and couldn't log back in to fix it. I edited the theme's functions.php and added

update_option('siteurl','http://example.com/blog'); update_option('home','http://example.com/blog');

After logging back into the website, I deleted these lines -- it's important to delete them!

Debian

• Debian Installation
• Look at packages.qa.debian for todo's and qa.debian under my name for all the bugs and other information.
• Popcon means popularity contest but there are people who install a package but don't use popcon.
• dpkg -l (package name): gives the version of the package.
• To upgrade to Squeeze (except I wanted testing = Wheezy):
  • change lenny to squeeze in /etc/apt/source.list
  • apt-get update
  • apt-get install apt dpkg apt
  • apt-get dist-upgrade: error message telling me /var/cache/apt/archives doesn't have enough space. Ran aptitude clean and it was cleaned up.
  • I changed to Wheezy because I wanted Gnome3.2. I changed on the /etc/apt/source.list.

Inkscape

• I wanted to use a landscape canvas: Go to File -> Document Property - Choose Landscape.

• I wanted to use text: Press F8.

Bug Report

• I have trouble using Inkscape because it crashes when I try to use text. Here's how to get a backtrace:

gdb <path to inkscape executable>

(gdb) run [parameters (optional)]

# Carry out the actions to make the program crash

(gdb) bt

R

• expression and assignment

PHP

Problem:

Again, I was doing this tutorial. I got the update/delete working but not insert. Even when I typed in the values, it returned Missing Values.

Solution

I said name="id" in select3.php in the form part for insert3.php but I said _POST[ID] in insert3.php. I changed it to id and it works fine now.

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Problem:

I was doing this tutorial. First of all, I didn't quite write down the codes right:

• incorrect update/delete versions linked from select.php
• <?= is good <? = is not good
• _GET['X'] is good but _GET["X"] is not good.
• Don't free memory in the php that is required_once

After fixing all these, I got:

"failed query" SQL:SELECT Name WHERE ID =

Solution

Since I got the same message for both update and delete, I figured that the problem was elsewhere. I looked at select3 and after update3.php? I said id= instead ID= . I capitalized the id for bother update3 and delete3 and it works fine now.

MySQL

To be sorted:

• http://mysqlweb.net/category/4025593-1.html
• http://dev.mysql.com/doc/refman/5.0/en/join.html
• http://dev.mysql.com/doc/refman/5.1/en/selecting-rows.html
• fetchone() doesn't take an argument: http://python-sybase.sourceforge.net/sybase/node10.html
• http://www.cyberciti.biz/tips/recover-mysql-root-password.html

Cheat Sheet

• command line to restart mysql: /etc/init.d/mysql start
• check ps fax for mysqld to see if the mysql server is running.
• mysql_connect()
• mysql_select_db()
• mysql_query()
• mysql_num_rows()
• mysql_free_result()
• mysql_close()
• This is for outputting mysql queries into a text file: mysql > select * from table INTO OUTFILE '/tmp/test.txt';

Problem:

I tried to write a php and connect to mysql in it but I got an error:

Fatal Error: undefined function mysql_connect()

Solution:

This page suggested that mysql isn't enabled by dafault in php5. I installed php5-mysql and restarted apache2 (don't know if that was necessary) and now it works.

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Problem:

I restarted my computer because I couldn't start gimp unless I was root. Clint told me that I should sudo /etc/init.d/dbus restart , which basically restarted my whole computer. Since then, I couldn't use mysql because I kept getting this error:

ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)

Solution:

I followed this and restarted mysql by:

/etc/init.d/mysql restart

But it fails. It seems like I touched my.cnf and didn't restart mysql, so when my computer restarted, it incorporated the changes I made in my.cnf and mysql stopped working. I reinstalled mysql-server through apt-get, restarted mysql and now it's fine.

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Problem:

I have a bunch of text files from USDA, which contain bits and pieces USDA ASCII databases. I want to put them into mysql.

Solution:

1. I found schema.sql that Erik created, so I'm going to borrow it rather than creating my own.

mysql databasename < schema.sql -p

Problem:

mysql> create database newdatabase;

ERROR 1044 (42000): Access denied for user 'user'@'localhost'...

Solution:

mysql

1. Check grants for 'user'@'localhost' in mysql:

mysql> show grants for 'user'@'localhost';

2. Log into mysql as root (has all privileges) and change grants for a specific user:

mysql> grant all privileges on *.* to 'user'@'localhost';

Query OK, 0 rows affected (0.00 sec)

3. Log back into mysql as user (now has all privileges) and try creating a new database again.

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Python

To be sorted

• http://mysql-python.sourceforge.net/MySQLdb.html
  • http://www.devshed.com/c/a/Python/MySQL-Connectivity-With-Python/2/

• TypeError: fetchone() takes exactly 1 argument (2 given)
  • This really means 1 argument given because each method comes with an argument to begin with.

• To obtain input, I can use raw_input().
• bpython

Problem:

I wanted to create a wiki table from CIA's Infant Mortality Rate ranking data. I didn't want to change to the wiki table format, so I decided to write a python code.

Solutions:

I had to read a text file, make a list for each line, take out the words I need, and print in the wiki table format. I did the following first to change tabs to commas but that was probably not necessary:

    sed 's/\\t/,/g' Desktop/rawIMRdata.text > rawIMRdata2.text

When I forgot /g, it only outputted the last line.

Here's the python code:

    imr_data = open("rawIMRdata6.text")
    #f = file("imr_data","r")
    print {| class="wikitable" border="1" \n|- \n!  Ranking 1 \n!  Country 2 \n!  IMR \n
    for line in imr_data.readlines():
        # To make a list for each line from text file:
        a = line.split(',')
        #print a and strip the space after each word
        one = a[0].strip()
        two = a[1].strip()
        three = a[3].strip()	
        combined = '|-\n|' + one + '\n|' + two + '\n|' + three   
        print combined
    print r|}

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Django

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• Tried setting up Django on my computer by following this tutorial

Problem:

It worked mostly ok but I couldn't go further than the second to the last coding box on page 4. I kept getting long error messages.

Solution:

Django tutorial about django.contrib.admin

1. Check if I typed in the correct codes.

2. Check if the output are the same everwhere:

Although the codes were correct, they didn't create all the necessary things, so it couldn't find the index.html.

• I went to setting.py to specify:
  • the absolute path for Template_Dir. Don't forget the , after '/path/' .
  • two additional Installed_Apps: myprj_myapp (where I save my project) and django.contrib.admin . Run python manage.py syncdb afterwards.

This created myapp_post and django_admin_log in mysql database.

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Javascript

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JS Tutorial

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HTML/CSS

Problem I couldn't put the content and the sidebar side by side.

Solution CSS: added floar:left to content.

Problem: I didn't know how to align text on both sides in html or css.

Solution: HTML: p style="text-align:justify CSS: p.special {text-align:justify;}

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Problem:

I didn't know what meant.

Solution:

This website says: An HTML table has two kinds of cells:

   * Header cells - contains header information (created with the th element)
   * Standard cells - contains data (created with the td element)

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Problem:

I didn't know what <form name="form1"> meant.

Solution:

"A form is an area that can contain form elements.

Form elements are elements that allow the user to enter information (like text fields, textarea fields, drop-down menus, radio buttons, checkboxes, etc.) in a form." とほほのjavascript

GPG/PGP

• Websites of interest:
  • http://www.madboa.com/geek/gpg-quickstart/
  • http://ekaia.org/blog/2009/05/10/creating-new-gpgkey/
  • https://www.debian-administration.org/users/dkg/weblog/48

1. Make a gpg key. 2. Register on pool.sks-keyservers.net.

• To open a pgp signed email in mutt, first imap-fetch to my email inbox. If the encrypted message doesn't ask my passphrase, download the attachment (hit v, download no description. file (the file name) should say PGP message), and run: gpg --output (outputfile.txt) --decrypt (downloaded file name). Enter passphrase.

GNOME

• Switch windows when a mouse moves over without a click: System -> Preference -> Windows

Wiki tricks

• insert : to make a single indentation. Insert more for multiple indentation.
• insert < blockquote> makes a paragraph blockquote -- couldn't find ways to insert breaks between lines within a blockquote.
• insert < code>

Command line

• arch: get architecture info
• uname -a: print system info
• xev: finds information on the pressed keys
• xmodmap -e "keycode ###=Multi_key": Enter the key number in ### to set the compose key.
• import -windows root screenshot.png: Takes a screenshot of the entire screen instead of a window.
• sudo acpi -V: tells me the temperature of my computer.
• cat /etc/issue: gives the current version of Ubuntu.
• cat /etc/debian_version: give the current version of Debian.
• rsync -rP: synches data with the options recursive and partial.
• ssh-keygen -p: lets me change the ssh password.
• df -h: sizes for disk space.
• du -h: sizes for all folders.
• du -sk /* | sort -n: sort everything by size in /.
• curl (url): prints out the content of the link.
• bash (wordpress upgrade scrip) instead of sh because /bin/sh is no longer bash.
• zcat access.log.*.gz | visitors -