Things I know I'll forget sooner or later…
Create a new file in the /etc/apt/apt.conf.d
for example: create the file 80proxy with
sudo nano /etc/apt/apt.conf.d/80proxy
and add the following lines to configure the proxy setting:
Acquire::http::Proxy "http://<username>:<password>@<proxy IP>:<port>";
Acquire::https::Proxy "http://<username>:<password>@<proxy IP>:<port>";
Acquire::ftp::Proxy "http://<username>:<password>@<proxy IP>:<port>";
Today, I had to convert a scanned 3-page PDF file back into a editable document. So, open source software to the rescue. I was able to complete the task with the help of:
sudo apt-get -y install tesseract-ocr imagemagick
convert -density 300 -depth 8 scan.pdf[0] scan0.png convert -density 300 -depth 8 scan.pdf[1] scan1.png convert -density 300 -depth 8 scan.pdf[2] scan2.png
convert is a member of the amagemagick tools. You can use it to convert between image formats as well as resize an image, blur, crop, despeckle, dither, draw on, flip, join, re-sample, and much more.
Here, I’m only using two options:
-density width
to set the resolution of an image for rendering to devices. The default unit of measure is dots per inch. The default resolution is 72 dpi.
-depth value
to set the number of bits in a color sample within a pixel.
The numbers between the brackets mark the page in the PDF document to be converted. Of course, as any programmer can tell you, you start counting at zero.
$ tesseract scan0.png scan0.txt Tesseract Open Source OCR Engine v3.02.01 with Leptonica $ tesseract scan1.png scan1.txt Tesseract Open Source OCR Engine v3.02.01 with Leptonica $ tesseract scan2.png scan2.txt Tesseract Open Source OCR Engine v3.02.01 with Leptonica
And then just copy the OCR text from the text files into a new document to clear up any typo and reformat the document.
ls uses the environment variable LS_COLORS to determine the colors in which the filenames are to be displayed. This environment variable is usually set by a command in the .bashrc file like
eval 'dircolors some_path/dir_colors'
to create a customize .dircolors file, use the command
dircolors -p > .dircolors
and then edit the .dircolors file.
for example, change the color of execute permission to red with: EXEC 00;31
The comments in the generated .dircolors file already listed the color codes.
ISO 6429 color sequences are composed of sequences of numbers separated by semicolons. The most common codes are:
| Attribute Codes: | |
|---|---|
| 00 | none — to restore default color |
| 01 | bold — for brighter colors |
| 04 | underscore — for underlined text |
| 05 | blink — for flashing text |
| 07 | reverse — to reverse background and foreground colors |
| 08 | concealed — to hide text |
| Text Color Codes: | Background Color Codes | ||
|---|---|---|---|
| 30 | for black foreground | 40 | for black background |
| 31 | for red foreground | 41 | for red background |
| 32 | for green foreground | 42 | for green background |
| 33 | for orange foreground | 43 | for brown background |
| 34 | for blue foreground | 44 | for blue background |
| 35 | for purple foreground | 45 | for purple background |
| 36 | for cyan foreground | 46 | for cyan background |
| 37 | for gray foreground | 47 | for gray background |
| Extra Text Color Codes: | Extra Background Color Codes | ||
| 90 | dark gray | 100 | dark gray background |
| 91 | light red | 101 | light red background |
| 92 | light green | 102 | light green background |
| 93 | yellow | 103 | yellow background |
| 94 | light blue | 104 | light blue background |
| 95 | light purple | 105 | light purple background |
| 96 | turquoise | 106 | turquoise background |
| 97 | white | 107 | white background |
Copy font file to font directory at
/usr/share/fonts/truetype
or for a specific user, put the font files in
/home/<username>/.local/share/fonts
refresh cache with
fc-cache -f -v
Note: fc-cache is part of the fontconfig package.
I normally use the US-Dvorak keyboard layout, but for some typing in foreign languages, I like to switch back to the basic US keyboard layout. On other Linux distros it’s I had use the keyboard setting graphic user interface to set up the two US keyboard layouts, and then assign a key combination to switch between the two (personally, I like to hold down both the left and right shift-keys for the switch.)
However, on Linux Mint 12 LXDE, I could not find a graphic interface that would allow me to load the two keyboard layouts and assign the switch key combo.
Here’s what I found out about setting my desire layouts and hot-key the manual way:
Per session setting, at the command terminal use the setxkbmap command:
setxkbmap -layout "us,us" -variant "dvorak,basic" -option "grp:shifts_toggle"
For a more permanent configuration, edit the /etc/default/keyboard file and change the XKB-variables:
XKBMODEL="pc105" XKBLAYOUT="us,us" XKBVARIANT="dvorak,basic" XKBOPTIONS="grp:shifts_toggle"
