Idea for a simple bib tool

I was using Zotero for my research readings, however, it is a bit too heavy for me, and I want a tool that can be portable across machines. So I am planning to write a bib tool for myself when I am a bit free sometime next spring.

The most important concept in this tool:

• Keep it Simple: there will NOT be fancy setup interface, but a config XML; there will not be many export styles for that is latex’s business.
• Depend less: there is already many advanced tools for bib organization, but they depend on this and that. I plan to implement all this tool with Python and sqlite3, so it can be put into U-key/Dropbox, and used anywhere.

The basci senarios is:

1. User start the tool, which set up a local web sever at a high port (eg: 8080), and open any browser to land on the interface.
2. To add a new paper, user have to
   1. upload a pdf file
   2. add bibtex info by
      1. upload a crospending a bibtex file
      2. fill a form to generate bibtex info
   3. add optional tags
   4. add optional note
3. To view paper:
   1. start a search (empty field means any)
   2. a list of reference is returned
   3. (optional) open pdf file
4. To export
   1. start a search
   2. select paper and add to “basket”
   3. go to export folder and get a sorted bib for all and BIB’s for each files and copies of PDF’s

Suggestions are always welcomed :)

SumatraPDF is really FAST

I have reading a lot of pdf files recently, and I often open a file, read a handful paragraphs and close the file. While Adobe Reader provides great render quality, it is a bit slow.

So I turned to SumatraPDF, which is an open source pdf reader based on MuPDF and brings several useful functionalities, such as searching and copy.

What in_lto_p has _p suffix in GCC 4.5

Abstract: Curiosity killed the cat XD

Usually we use _p suffix to pointers in C language, but it is not the case for in_lto_p in GCC 4.5, so I searched for the reason, and according to <http://www.stanford.edu/~blp/writings/blp-stds/blp-stds_4.html> :

p-convention

A _p suffix indicates a boolean test for the condition described by the rest of the name. (This comes from Lisp.)

And it can be supported by this wiki page<http://en.wikipedia.org/wiki/P_convention> :

This practice originated among users of the Lisp programming language, in which there is the convention of appending the letter “P” on elements to denote a predicate (a yes or no question). It is most commonly used at MIT and the University of California, Berkeley, or among computer scientists working in Artificial intelligence (which frequently uses Lisp).

So _p for predicate not pointer here :)

Bash environment memo: profile, bash_profile & bashrc

Abstract: I'm trying to explain the process of bash setup in this article.

Keywords:bash, shell, environment

It is usually hard to answer the question where this variable is set, because there is SO many different files involved. So let's start with some concepts:

interactive login shell

The shell started after a successful login, using /bin/login, by reading the /etc/passwd file.

interactive non-login shell

It is normally started at the command-line using a shell program (eg.$/bin/bash) or by the /bin/su command. It is also started with a terminal program within a graphical environment.

non-interactive shell

It's usually used to execute a shell script

An interactive login shell generally initializes with the following configuration files:

/etc/profile -> [~/.bash_profile] -> [~/.bash_login] -> [~/.profile]

In some systems, the /etc/profile script will look for additional settings in /etc/profile.d/*.sh, and the ~/.bash_profile usually sources ~/.bashrc.

When an interactive non-login shell starts, it first copies the environment of its parent shell and then reads its settings in the following order:

/etc/bash.bashrc -> [~/.bashrc]

Remember that only exported variables of its parent shell is copied, functions and aliases of its parent are NOT inherited.

A non-interactive shell simply copies environment from its parent, and does not read any configuration files.

Mount internal filesystem without passwd with devicekit-disk

Abstract: Use policykit to avoid password for mount an internal filesystem.

Last week, I updated my Arch Linux laptop, and got the new deviekit-disk. Then I found that the authorizations set with gnome interface, which actually sets theorg.freedesktop.hal.storage..., stops work. I have to give the root passwd when I try to mount an internal filesystem, which is really bothering:(

Luckly it is not hard to solve this problem with Policykit, though there dosen't seem to be a sweet GUI to help. All you have to do is simply create a text file named anything in /var/lib/polkit-1/localauthority/50-local.d/and fill it with the content below:

[internal filesystems mount privs]
Identity=unix-group:storage
Action=org.freedesktop.devicekit.disks.filesystem-mount-system-internal
ResultAny=no
ResultInactive=no
ResultActive=yes

Here I allow the group named storage to mount internal filesystem without root password. you should subustitute it with your group or allow some user instead:

Identity=unix-user:yourname

You can always man pklocalauthority for more info:)

looking for a web software for knowlege sharing

I am currently looking for a web-based software for knowledge sharing in our lab, I've investigated some blog, cms and also wiki softwares, but none seems to fit :(

We just want something which is easy to setup and maintain, and can organize different kind of materials. CMS's are powerful, but relatively hard to used...Wiki seems to lack some kind of structure. Blogs are easy to use, but does not organize resources well.

So what do you use in your lab, my dear readers?

QEMU "host only network"

Abstract: Setup an LAN network of only the host and guest.

Recently I'm trying something on qemu and want to access the guest from the host more freely than user mod port redirect, but I do not want to expose my guest to the host network. All I did is to wrap everything into a script:

#!/bin/sh

HOSTIP="192.168.1.250"
GUESTIP="192.168.2.10"
NETMASK="255.255.255.0"
USERID=`whoami`
IFNAME=`sudo tunctl -b -u $USERID`

sudo ifconfig $IFNAME $HOSTIP netmask $NETMASK up

echo ":: Host IP is $HOSTIP"
echo ":: Run the follwing command in guest to set IP and gateway:"
echo " # ifconfig eth0 $GUESTIP"
echo " # route add default gw $HOSTIP"
echo ":: Starting QEMU with TUN/TAP network..."

qemu -hda webdev.qcow \
     -boot c -m 256 \
     -k en-us -localtime\
     -net nic,vlan=0,model=rtl8139 \
     -net tap,vlan=0,ifname=$IFNAME,script=no,downscript=no

sudo tunctl -d $IFNAME
HOSTIP="19

Btw, I find sticky note gadget on iGoogle a great tool to share a couple of lines between machines - I'm writing on my Windows laptop and the script is in my Linix desktop, just a few paste and copy brings the script here :)