FilipiVianna

In my post " Plotting memory usage on console " the chart doesn't pan the data. Now, using a named pipe, the effect got a little bit nicer. First, we have to run the memUsage.sh script to get a file filled with memory usage info: ./memUsage.sh > memUsage.dat & Then we have to create a named pipe: mkfifo pipe Now we have to run another process to tail only the last 64 lines from the memUsage.dat while [ 1 ]; do tail -64 memUsage.dat> pipe; done & And now we just have to plot the data from the pipe: watch -n 1 'gnuplot -e "set terminal dumb;p \"pipe\" with lines"' And that is it!

This is just a simple hack to play around with gnuplot set to dumb terminal (character console), doesn't meant to be serious application. First I had written a bash scritp to log memory usage a while ago: So, while running this script in background ( ./memUsage.sh > memUsage.dat & ), logging the data, the memory usage information can be plotted with gnuplot and watched in real time: watch -n 1 'gnuplot -e "set terminal dumb;p \"memUsage.dat\" with impulses"' The chart can be plotted with lines, with impulses or any gnuplot style option .

Looking for some way to convert power point slides to JPG, I've found this site: http://www.commandlinefu.com/commands/browse It has tons of good linux command line tips. And here is the tip about the pdf to jpg which brought me there: http://www.commandlinefu.com/commands/view/719/convert-pdf-to-jpg And to convert the powerpoint to pdf before, one can issue the unoconv command: unoconv -f pdf slides.ppt

One can do more than simple convert vector to raster drawings with inkscape from the command line. In fact, there are other tools if the goal is just converting files, as rsvg and convert. With inkscape, is also possible to change the drawing, using verbs . From the inkscape man page , we can find the folowing example: Duplicate the object with id="path1555", rotate the duplicate 90 degrees, save SVG, and quit: inkscape filename.svg --select=path1555 --verb=EditDuplicate --verb=ObjectRotate90 --verb=FileSave --verb=FileClose Googling a little on inkscape "--verb" , I did find more examples , a list with the available verbs and details from the inkscape wiki .

Since I've upgraded to Ubuntu 10.04 (Lucid) Emacs 23 now has beautiful antialiased fonts, but I like the old bitmaped X11 "fixed" font. I do use a .Xresources file to setup emacs default font. This is my emacs section at .Xresources !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! ! emacs, xemacs !emacs*Background: DarkSlateGray emacs*Background: Black !!!emacs*Foreground: Wheat emacs*Foreground: White emacs*pointerColor: Red emacs*cursorColor: Red emacs*bitmapIcon: on emacs*font: fixed !!!emacs*font: 9x15bold !!emacs*geometry: 100x40+20+20 But for my surprise using this setup emacs launches with a ugly huge serif font. I tried to launch emacs with -fn fixed but the ugly font did still there. So I checked at my /etc/X11/fonts/misc/xfonts-base.alias, which is the file where fixed font is declared. And it was there: fixed -misc-fixed-medium-r-semicondensed--13-120-75-75-c-60-iso8859-1 And which had called my attention, was that 6x13 font alias had the same properties as the fixed:...

I have an ATI Raden dual head at my desktop here at my job. I like to use WindowMaker as my window manager of choice, but since I had upgraded to Ubuntu 10.04 Lucid, WindowMaker is showing some issues regarding the dual monitor setup. WindowMaker follows the login screen (GDM) monitor setup and when I launch a gnome-session, things get messed up. The first solution which came to my mind is to make gdm aware of the two monitors. "Googling" around I've found two usefull links: https://help.ubuntu.com/community/MultiseatOneCard http://ubuntuforums.org/showthread.php?t=1611704 Following the first section of the first link ("Extended desktop through both monitors") I've wrote my new xorg.conf file: Section "Monitor" Identifier "monitor0" EndSection Section "Monitor" Identifier "monitor1" Option "RightOf" "monitor0" EndSection Section "Device" Identifier "card0...

I am facing a terrible issue regarding timing on windows. Googling arround, I've found those infos: Using QueryPerformanceCounter and QueryPerformanceFrequency APIs in Dev-C++ ( http://yeohhs.blogspot.com/2005/08/using -queryperformancecounter-and_13.html ) QueryPerformanceCounter() vs. GetTickCount() http://www.delphifaq.com/faq/delphi_windows_API/f345.shtml How to time a block of code http://www.cryer.co.uk/brian/delphi/howto_time_code.htm And Results of some quick research on timing in Win32 http://www.geisswerks.com/ryan/FAQS/timing.html With that I'm trying to write something like a uSleep function for windows: # include<windows.h> void uSleep ( int waitTime){ __int64 time1 = 0, time2 = 0, sysFreq = 0; QueryPerformanceCounter((LARGE_INTEGER *)&time1); QueryPerformanceFrequency((LARGE_INTEGER *)&freq); do { QueryPerformanceCounter((LARGE_INTEGER *)&time2); // }while((((time2-time1)*1.0)/sysFreq)<waitTime); } while ( (time2-time1) <waitTime); } T...

Working supporting old scientific hardware sometimes brings me some challenges. Usually, the manuals are only on paper and when there is a digital version it was digitized (scanned) . Googling a little, came to me an article which relies on waiting for the google to index your files and OCR them. But there is an open source alternative. Looking a little further, I did find another two articles at linuxquestions.org and at linux.com , on which I've found the tesseract-ocr . So to solve my issue, I had to first convert my PDF file to a bunch of TIF images, and so OCR them with tesseract. This way: gs -dNOPAUSE -sDEVICE=tiffgray -r300x300 -sOutputFile=page%03d.tif -- 1850_operators_manual.pdf ls -1 *.tif | cut -d e -f 2 | while read line ; do tesseract "page"$line "page"$line -l eng; done Hope this helps somebody...

I do use GNU Emacs for almost every text file related thing. Functions like search, replace, cut, paste, etc are all quickly mastered. But, then I've faced a different situation. I had to replace a string, repeat some numbers and put another string. The answer: regular expressions. Emacs has a regular expression replace function. To access it, just type: "Ctrl + Alt + Shift + 5" (too much keys huh... ?) And it asks what should be searched. In my case, in which I wanted to capture the regex match, I did type \([0-9][0-9][0-9]\) to locate a 3 digit numbers and capture them. Then I typed enter and did tell Emacs what it should put in those numbers place: ID=\1; mv \1 ./safebox/\1 And enter again and ! to replace all. That is it.

Hack a Day has exactly the tutorial I am needing: Introduction to FTDI bitbang mode . It is also a Windows Serial thought USB programming tutorial for dummies.

Regex (Regular expressions) are very useful. I had to make a SQL query to return only the firstname from a table where the field provides the full name. ideia_onde=# SELECT name FROM users; name -------------------------------- Linus Torvalds Randal Schwartz Steve Wozniak (3 rows) ideia_onde=# Now, with a simple substring using a regular expression: SELECT SUBSTRING(name, '(.*?(\\s))') FROM users; substring ----------- Linus Randal Steve (3 rows) ideia_onde=# What do I did? The substring function extracts from the name field everything (.*) until (?) a space character (\\s).