Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I know an ASCII character takes 8 bits but how do you print a character on screen with those bits?

share|improve this question
What operating system? Where? command line? programming language? – Mikel Jan 24 '11 at 21:44
ASCII actually only takes 7 bits. – Ignacio Vazquez-Abrams Jan 24 '11 at 21:44
I really meant how a character is represented on screen. How does 7 bits make up a 'character print'. – user32344 Jan 24 '11 at 21:46
up vote 3 down vote accepted

The byte is used as a lookup in a font table, and the appropriate pixels are lit for that character at the appropriate position.

share|improve this answer
What could be the maximum number of pixels allowed for character? – user32344 Jan 24 '11 at 21:47
not only "the byte" but also (in unicode environments) any other glyph. you take the 'code', search for the visual representative in a lookup table and then you render it. ignacios answers is the correct one. – akira Jan 24 '11 at 21:48
@user32344: you can lookup a glyph in a vector font ... so you can render it with as much pixels as you like. – akira Jan 24 '11 at 21:49
It is completely dependent on the mechanism used for displaying the pixels on-screen, but a 8×16 cell is usually more than enough for PC text mode. – Ignacio Vazquez-Abrams Jan 24 '11 at 21:49
@user32355 Most fonts these days are represented by vector information. That way there is virtually no maximum size limit to the font. – BloodPhilia Jan 24 '11 at 21:50

You mean rather than doing

echo a

You want to type

echo 00111101

or something?

I think you'd have to convert it from binary to octal first. Then you can do:

echo -e "\0141"
share|improve this answer
$ printbin () { printf "\\$((2#$1/64*100+2#$1%64*10+2#$1%8))\n"; }
$ printbin 1000001
$ printbin 1100001
share|improve this answer

In Windows, you can use a character's Alt character code to print it by pressing Alt + [code] on the Numpad. In some cases, the Alt character code coincides with its Unicode character code.

Example: Alt + 250 = ú

You can find the whole list of Alt codes by running the Character Map applications (charmap.exe).

share|improve this answer
-1: The code isn't Unicode. It's the Windows Alt Key code – Wuffers Jan 24 '11 at 22:18
You're right. However, many Alt Key codes coincide with the character's Unicode character code. Sorry for the confusion. – Juliana Peña Jan 25 '11 at 2:23
yep.. the ascii codes do overlap unicode. it's also possible to type unicode(in hex) from the numpad, but entering unicode like that may be dependent on application +1 to cancel the downvote of -1! – barlop Jan 30 '11 at 12:45

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.