“Qalculate! is a multi-purpose desktop calculator for GNU/Linux (now ported to Mac). It is small and simple to use but with much power and versatility underneath. Features include customizable functions, units, arbitrary precision, plotting, and a user-friendly interface (KDE or GTK+).” (source)
The software has a command-line interface too that you can start with the command “
qalc“. You can do all kinds of fancy math calculations with it, but this time I’m interested in currency conversions. Qalc supports it too:
$ qalc You need the download exchange rates to be able to convert between different currencies. You can later get current exchange rates with the "exchange rates" command. Do you want to fetch exchange rates now from the Internet (default yes)? yes > 50000 USD to HUF 50000 * dollar = approx. HUF 12157958 > USD to HUF dollar = approx. HUF 243.15915 >
- x-rates.com currency calculator (web-based)
Total Commander has a nice feature: if you press Backspace, it steps back to the parent directory. How to have this shortcut in Midnight Commander?
This thing has bugged me for years! But, I was lazy to look it up. Today I got fed up and made a Google search. Guess what. I had the answer in 5 minutes…
The local config files of MC are here:
~/.config/mc. The global ones are located at
/etc/mc. I like to access the local config files at ~/.mc, so first I create a symbolic link:
$ cd $ ln -s ~/.config/mc .mc $ cd .mc $ cp /etc/mc/mc.keymap . $ vi mc.keymap
Modify this line:
# new value: CdParentSmart = backspace
Originally this line was put in comment.
Restart MC and enjoy the new feature. If you wrote something in the mini shell, you can still delete it with the Backspace. If the mini shell is empty, Backspace makes MC jump back to the parent directory.
My MC version is 4.8.13. You can verify yours with “
They support a lot of tube sites.
I have a Huawei Ascend Y200 device and lately it was acting strangely. This device doesn’t have much memory, so it was always complaining about low memory but I got used to it. Installing a new app was always a pain or simply impossible… But a few days ago it was dropping error messages like “process com.google.process.gapps has stopped”. Due to this problem I couldn’t use my phone normally. For instance, when I wanted to check my text messages, it quit to the desktop all the time.
The solution is very simple: remove as many apps as you can to free some RAM for the device. I did this and after a restart it works like a charm.
I was already thinking that I should buy a new device, after all it’s 2 years old, but now it works fine. I give it another chance :)
When I got this mobile, I used it for lots of things: watch movies, play music, browse YouTube, etc. Thus, I installed several apps that filled up its memory. Since then I got a tablet, which is much better for these tasks, so I could remove these extra apps from the mobile without hesitation. Now, as it has some free RAM, it can work correctly. Well, after all, what should this device know? Make phone calls, write SMS messages, have an alarm clock, and sometimes check my emails. That’s all.
You have an image with some text / digits, and you want to convert it to text. Then you can process the text with a program easily.
Use an OCR. Let’s see two free solutions:
“Tesseract is probably the most accurate open source OCR engine available. Combined with the Leptonica Image Processing Library it can read a wide variety of image formats and convert them to text in over 60 languages. It was one of the top 3 engines in the 1995 UNLV Accuracy test. Between 1995 and 2006 it had little work done on it, but since then it has been improved extensively by Google. It is released under the Apache License 2.0.” (source)
Under Ubuntu you can install it with the good old
Print the result to the standard output:
$ tesseract numbers.jpg stdout 01234 56789
Print the result to a file:
$ tesseract numbers.jpg output $ cat output.txt 01234 56789
As can be seen, the extension “
.txt” is added automatically.
(2) online OCR
Just google “online OCR” :) Free OCR worked pretty well for me. Just upload your image, fill out a captcha and there you go.
When I started to use Linux, I played movies with mplayer. Then the development of mplayer seemed to slow down (stopped?) and I switched to VLC. VLC is very easy to use and it plays everything, so I’m very satisfied with this player.
A few days ago I discovered mpv, which is a fork of mplayer2 and MPlayer. It shares some features with the former projects while introducing many more.
It seems that mplayer and mplayer2 are dead, but mpv is developed actively (check it out on github).
I just ran through its feature list and I saw that if you quit with Shift-q (i.e. Q), then mpv will resume from that position next time you start the same movie. Cool.
So next to VLC you can keep mpv too.