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Thomas Thompson
Thomas Thompson

Osx Terminal How To Get Hex Code For Acharacter



To use the keyboard directly with their code numbers, first enable Unicode Hex Input in System Preferences -> Keyboard -> Input Sources. Then, each time you wish to use that input method, switch to the Unicode Hex layout (this can be done via a keyboard shortcut that by default conflicts with spotlight) and then hold the option/alt modifier while you type the the utf-16 hex codes you wish (which is really two hex codes for characters beyond the Unicode BMP, such as 1f4a9, which is represented by d83d dca9).




Osx Terminal How To Get Hex Code For Acharacter



In System Preference, select "Keyboard", then select "Input Sources". The left hand pane will show your preferred language keyboard, and possibly alternates. If Unicode Hex Input is not there, click the + button beneath; you will get a long list of languages. Scroll to the very bottom and choose others. Unicode Hex Input will appear in the right pane, then click the Add button, bottom right.


If I use a pipe then the second argument -, which means stdin, will never match any bytes since all the standard input will go to the first one. When using a terminal instead of a pipe, I can type Ctrl + D so the first one gets 'closed' and the second one start reading.


Am I being completely stupid? Or is there really something strange with sed? It can apparently interpret the hex code in a range, but I can't get it to be interpreted as a single character. What am I missing?


Please note - I am looking for answers that both explain why the above is behaving the way it is, and for ways to make it possible to insert a single hex code anywhere in a sed string, on the OSX platform. This means both in the "search", and in the "replace" part of the s/ command. Because I have obviously shown I can search for a single character with [\xnn-\xnn]; that's not the answer I am looking for.


There is no general concept of what "the OS and its functions understand" -- each program, function, etc understands its own particular set of metacharacters, escapes, etc. And it just happens that sed doesn't do hex codes. But bash does (if you ask it to), so you can have it translate them before calling sed with $'':


Unicode input is the insertion of a specific Unicode character on a computer by a user; it is a common way to input characters not directly supported by a physical keyboard. Unicode characters can be produced either by selecting them from a display or by typing a certain sequence of keys on a physical keyboard. In addition, a character produced by one of these methods in one web page or document can be copied into another. In contrast to ASCII's 96 element character set (which it contains), Unicode encodes hundreds of thousands of graphemes (characters) from almost all of the world's written languages and many other signs and symbols besides.[1][better source needed]


A Unicode input system must provide for a large repertoire of characters, ideally all valid Unicode code points. This is different from a keyboard layout which defines keys and their combinations only for a limited number of characters appropriate for a certain locale.


An application can display a character only if it can access a font which contains a glyph for the character.[2] Very few fonts have full Unicode coverage; most only contain the glyphs needed to support a few writing systems. However, most modern browsers and other text-processing applications are able to display multilingual content because they perform font substitution, automatically switching to a fallback font when necessary to display characters which are not supported in the current font. Which fonts are used for fallback and the thoroughness of Unicode coverage varies by software and operating system; some software will search for a suitable glyph in all of the installed fonts, others only search within certain fonts.


Clause 5.1 of ISO/IEC 14755 describes a Basic method whereby a beginning sequence is followed by the hex number representation of the code point and the ending sequence. Most modern systems have some method to emulate this, sometimes limited to four digits (thus only the Basic Multilingual Plane).


Hexadecimal Unicode input can be enabled by adding a string type (REG_SZ) value called EnableHexNumpad to the registry key HKEY_CURRENT_USER\Control Panel\Input Method and assigning the value data 1 to it. Users will need to log off and back in after editing the registry for this input method to start working. (In versions earlier than Vista, users needed to reboot for it to start working.)


Unicode characters can then be entered by holding down Alt, and typing + on the numeric keypad, followed by the hexadecimal code, and then releasing Alt.[2] This may not work for 5-digit hexadecimal codes like U+1F937. Some versions of Windows may require the digits 0-9 to be typed on the numeric keypad or require NumLock to be on.[citation needed]


In HTML and XML, character codes to be rendered as characters are prefixed by ampersand and number sign (&#), and are followed by a semicolon (;). The code point can be either in decimal or in hexadecimal; in the latter case it is preceded by an "x". Leading zeros may be omitted. A number of characters may be represented by a named entity.


One awesome feature of CoolTerm is Hex View. If you want to see the actual hex values of the data you are sending rather than the ASCII values, Hex View is a tremendous help. Click the View Hex icon. The terminal's appearance will change slightly. Now whatever you type will show up as hex and ASCII. The first column is just keeping track of line numbers. The second column is the hex values, and the last column is the actual ASCII characters you type.


Everyone is used to programs printing out output in a terminal that scrolls as new text appears, but that's not all your can do: your program can color your text, move the cursor up, down, left or right, or clear portions of the screen if you are going to re-print them later. This is what lets programs like Git implement its dynamic progress indicators, and Vim or Bash implement their editors that let you modify already-displayed text without scrolling the terminal.


There are libraries like Readline, JLine, or the Python Prompt Toolkit that help you do this in various programming languages, but you can also do it yourself. This post will explore the basics of how you can control the terminal from any command-line program, with examples in Python, and how your own code can directly make use of all the special features the terminal has to offer.


The way that most programs interact with the Unix terminal is through ANSI escape codes. These are special codes that your program can print in order to give the terminal instructions. Various terminals support different subsets of these codes, and it's difficult to find a "authoritative" list of what every code does. Wikipedia has a reasonable listing of them, as do many other sites.


Nevertheless, it's possible to write programs that make use of ANSI escape codes, and at least will work on common Unix systems like Ubuntu or OS-X (though not Windows, which I won't cover here and is its own adventure!). This post will explore the basics of what Ansi escape codes exist, and demonstrate how to use them to write your own interactive command-line from first principles:


The most basic Ansi escape codes are those involved in rendering text. These let you add decorations like Colors, Background Colors or other Decorations to your printed text, but don't do anything fancy. The text you print will still end up at the bottom of the terminal, and still make your terminal scroll, just now it will be colored text instead of the default black/white color scheme your terminal has.


See how the red color, starting from the printed Hello World, ends up spilling into the >>> prompt. In fact, any code we type into this prompt will also be colored red, as will any subsequent output! That is how Ansi colors work: once you print out the special code enabling a color, the color persists forever until someone else prints out the code for a different color, or prints out the Reset code to disable it.


Most terminals, apart from the basic set of 8 colors, also support the "bright" or "bold" colors. These have their own set of codes, mirroring the normal colors, but with an additional ;1 in their codes:


The next set of Ansi escape codes are more complex: they allow you to move the cursor around the terminal window, or erase parts of it. These are the Ansi escape codes that programs like Bash use to let you move your cursor left and right across your input command in response to arrow-keys.


Here, we split up the write that writes the "move left" escape code, from the write that writes the percentage progress indicator. We also added a 1 second sleep between them, to give us a chance to see the cursors "in between" states rather than just the end result:


Now that we know how to make a self-updating progress bar using Ansi escape codes to control the terminal, it becomes relatively easy to modify it to be fancier, e.g. having a ASCII bar that goes across the screen:


Make sure we have enough space to draw the progress bars! This is done by writing "\n" * count when the function starts. This creates a series of newlines that makes the terminal scroll, ensuring that there are exactly count blank lines at the bottom of the terminal for the progress bars to be rendered on


Perhaps next time you are writing a command line application that's downloading lots of files in parallel, or doing some similar kind of parallel task, you could write a similar Ansi-escape-code-based progress bar so the user can see how their command is progressing.


Of course, all these progress prompts so far are fake: they're not really monitoring the progress of any task. Nevertheless, they demonstrate how you can use Ansi escape codes to put a dynamic progress indicator in any command-line program you write, so when you do have something whose progress you can monitor, you now have the ability to put fancy live-updating progress bars on it. 350c69d7ab


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