I had sent a PDF file to a printer for printing. Then I was waiting for a person to finish her priting job. Unfortunately, an error occured, and she left without saying a word.
If I press the “Stop” button to continue with my work, she wouldn’t be able to know what’s wrong. Not hoping to get into any trouble with her, I had sent the job to another printer. I had finally got my copy of the document and returned home.
]]>A month ago, I wanted to print a picture. However, I didn’t know how to use GUI programs like LibreOffice or GIMP to print images with their actual size. I know that this can be easily done in M$ Paint.1
Nonetheless, as a free software supporter, I should refuse using proprietary softwares and seek free alternatives.
I finally used the lpr
command to print the picture because
commands won’t change like buttons in GUI programs.
lpr foo.png
: print foo.png
with the default page size, and the
picture will fit the page.lpr --natural-scale=nn%
: It took me an hour to find out this
option is the true answer to my question. I googled “print actual
size of picture linux” and entered a page in a knowledge
base.2 Actually, the contents are the same as those in
http://localhost:631
. I don’t know why the section “Image
Options” can’t be found in the CUPS manual.
CUPS" title="Mannual’ ‘cups man’" >
lpoptions -l
for viewing the list of the default
printer settings, and one may modify it through the CUPS’s web
interface. For example, one may use the option -o
Resolution=Photo
. Note that it’s case sensitive.PPI and DPI are different. The former is about the printer and is independent of the picture, while the later is for controlling the printing size of the picture.3
See this forum post for details. ↩
See Command-Line Printing in Linux in the IT Knowledge Base of the University of Tennessee System. ↩
See PPI vs. DPI: what’s the difference? by Alex Bigman in 99designs. ↩
When I used Simple Scan, Ubuntu’s GUI tool for scanning documents, I encountered an error—the program couldn’t detect my scanner.
How can I scan images from my scanner in Ubuntu?
The working principle GUI tools are much more complicated than its command line counterpart.
I’ll illustrate the idea by a typical component in GUI by borrowing other’s depication of the delegation model in Java GUI programming.
Source: yet another insignificant programming
notes2
In my opinion, the working principle of a button in GUI is much more abstract than that of the nervous system in a human body. One can learn about the bilogical principles through observations of concrete objects.
Source: Passnownow3
Therefore, I immediately googled the *nix command for scanning
documents, and came up with brscan-skey
. I ran it with the -l
flag, the it said that my scanner wasn’t registered.
# brscan-skey
# brscan-skey -l
XXX-XXXX : brotherX:busX;devX : USB Not registered
A comment for Brother MFC-465CN took me to Brother’s
documentation for Linux drivers, but finding the right page by viewing
the right hyperlink was too slow, so I searched the command and
restricted the results to those in Brother’s website. The page in the
official documentation inspired me to add the following lines just
before the last line of /lib/udev/rules.d/40-libsane.rules
.4
# Brother scanners
ATTRS{idVendor}=="04f9", ENV{libsane_matched}="yes"
I rebooted my computer and my scanner became “active”. However,
Simple Scan still couldn’t detect it. I followed the official
documentation and pressed “Scan” button on the device. It worked and
the scanned files with the TIFF format could be found under
~/brscan/
.
After an hour, when I ran the same command to list out the devices
that brscan-skey
could detect, I got no output.
However, I could still use the button on my scanner to produce scanned images.
Refer to Ubuntu Distribution Upgrade to 14.04 and Upgraded Ubuntu for details. ↩
Chua Hock-Chuan. (2014, March). Java Programming Tutorial. Retrieved 12:25, August 14, 2014, from http://www.ntu.edu.sg/home/ehchua/programming/java/j4a_gui.html#zz-3.1 ↩
Reflex and Voluntary Actions. (n.d.). In Passnownow. Retrieved 12:52, August 14, 2014, from http://passnownow.com/classwork-series-and-exercises-biology-ss3-reflex-and-voluntary-actions/ ↩
Scanner setting for normal user. (2013). In Linux Informations. Retrieved 13:53, August 14, 2014, from http://support.brother.com/g/s/id/linux/en/instruction_scn1c.html?c=us_ot&lang=en&redirect=on#u9.10 ↩
Last Saturday night, I used my Ubuntu Desktop to watch some videos. While it was playing, the recently upgraded Firefox suddenly hanged. The screen was freezed, and the sound continued to play. To avoid disturbing my neighbour, I muted the monitor speakers. I initially guessed that the newly upgraded Firefox didn’t work well with Linux kernel 3.2.0-61, which was released on May 2 2014. I forced the machine to halt by pressing the power button for a while. Then I switched on the computer again, and chose “Memtest86+” in the GRUB menu. Within several minutes, the words in the blue screen blurred due to some blinking dots.
Half a year ago, I also encountered similar error in the RAM. I paid HKD$80 for a technician in a computer repair shop to check the computer without checking the hard disk. Unluckily, after leaving the computer off for a few days, he couldn’t found any problem and concluded that that was a “hard disk problem”.
As a result, I studied some commands for merging logical volumes in different physical volumes into the same physical volume, so as to use less space in my computer.
Thus, I planned to uninstall unnecessary packages the next day.
This Sunday, I turned on my computer. Quick as a flash, the power button’s blue light changed to yellow, and the machine beeped.
I searched “dell desktop beep”, and Google showed some related searches. I clicked on “dell desktop beep codes”, and found the official documentation on beep codes. Though it was written for an older model in the same series, I believed that it could be applied to my model as well.
To correctly identify the problem, I booted the faulty desktop again, and heard four repetitive short beeps before a pause. According to the manual, the culprit was the RAM.
I could search for the suitable models of RAM for my desktop model, but it took time and the Internet is not always a reliable source of information. If I buy the wrong RAM, I’ll have wasted several hundred dollars. Therefore, I decided to take my desktop to a computer repair shop for replacing the RAM.
At noon, it was extremely hot, so I waited for a few hours and tried setting up Octopress on my laptop, which ran on Windows 7 because I would like to write something about the recent Vim error caused by my outdated VIMRC before I forgot the cause and the solution of error. I came across some errors with long and complicated error messages. As a user but not a developer, I couldn’t immediately figure out what happened. Eventually, I spent a whole night to solve technical problems before I started to write posts/pages hosted on the same blog in Vim on both Ubuntu and Windows. I will talk about that in greater detail soon.
Ironically, in the afternoon, the technician took less than 30 minutes to remove the old RAM and install the new one.
However, as a GNU/Linux user, I don’t think I need an anti-virus.1