How can I type special characters in Linux?

Question

In Windows, there is the possibility to type special signs from the keyboard by holding the Alt key and typing a few numbers, that depends on which sign you want to use. Does it work with Linux in the same way?

Answer 1

You can use Ctrl + Shift + U followed by the code in hexadecimal. (You only need to hold down Ctrl and Shift while typing the code.)

In 2025, holding the keys down while typing the number does not appear to work as described. See this answer instead.

Answer 2

X uses something called the compose key. By pressing Compose, some key, some key… in sequence, you can input characters. I have my compose key set to Menu; to type a © (copyright symbol), I would use Menu, o, c.

A full list of X compose key combinations can be found online (200 KiB), or locally in /usr/share/X11/locale/en_US.UTF-8/Compose.

In GNOME, the compose key can be set by going to Preferences → Keyboard → Layouts tab → Layout Options → Compose key position.

Answer 3

Inputting Unicode characters in Linux varies. The UTF-8 and Unicode FAQ has a section containing different input methods:

• Ctrl + Shift + U [Unicode code point in hexadecimal] is defined in ISO 14755 and implemented by GTK 2+, and works in GNOME Terminal and other applications.
• Ctrl + V u [Unicode code point in hexadecimal] works in Vim.
• Alt+[Unicode code point in decimal using numeric keypad digits] works at the console providing your environment is properly configured to expect UTF-8 (via the LOCALE or LANG environment variables). (unicode_start man page).

Other methods you could use:

• Cut-and-paste characters from a small input file containing the characters you want.
• Use xmodmap to remap keys in X (see the FAQ link above for examples).

Answer 4

Alternative way: Use Ctrl + Shift + u followed by the code in hexadecimal and Enter.

Unlike the accepted answer tells, do not hold down Ctrl and Shift while typing the code. Otherwise it may not work because it may conflict with some shortcut key of the application you are using, e.g. Ctrl + Shift + c in your terminal emulator. That may be a bug though.

This way works at least with xfce4-terminal, GNOME Terminal, LXTerminal, LibreOffice, mousepad, Chromium, and Firefox.

Answer 5

The Linux console also supports compose keys (The compose key is often Alt + AltGr or PrintScrn) - see How to define a Compose Key in terminal on the Unix and Linux Stack Exchange for details.

Answer 6

If you are a US key user and need to type special characters infrequently, I recommend switching your keyboard layout to the "us(altgr-intl)" variation-- that's XKB notation. Your keyboard will work normally unless you hold the right Alt key, also known "AltGr", then you will mostly be able to access the extra characters shown in blue here:

I say "mostly" because that's a screenshot of the main US International layout. I found the details of the "altgr-intl" variation defined in this file on Arch Linux: /usr/share/X11/xkb/symbols/us: Here are the differences defined there:

// five dead keys moved into level3:
┊key <TLDE> { [    grave, asciitilde,  dead_grave,   dead_tilde      ] };
  ┊key <AC11> { [apostrophe,quotedbl,    dead_acute,   dead_diaeresis  ] };
// diversions from the MS Intl keyboard:
┊key <AE01> { [        1, exclam,      onesuperior,  exclamdown      ] };
  ┊key <AD04> { [        r, R,           ediaeresis,   Ediaeresis      ] };
  ┊key <AC07> { [        j, J,           idiaeresis,   Idiaeresis      ] };
  ┊key <AB02> { [        x, X,           oe,           OE              ] };
  ┊key <AB04> { [        v, V,           registered,   registered      ] };
// onequarter etc (not in iso8859-15) moved to get three unshifted deadkeys:
┊key <AE06> { [        6, asciicircum, dead_circumflex, onequarter    ] };
  ┊key <AE07> { [        7, ampersand,   dead_horn,       onehalf       ] };
  ┊key <AE08> { [        8, asterisk,    dead_ogonek,     threequarters ] };

This alternate layout doesn't have the additional "dead keys" that the main International layout does.

The four columns in each array are Regular, Shifted, AltGr, AltGr Shifted.

So for example to type ¡ I press "<Shift-AltGr-1>".

You can search for an image of the US International layout until you remember the locations of the symbols you need.

Answer 7

There's a better method for both Linux and Windows than using Alt key codes that doesn't require you to remember any codes. It's described in detail here.

The gist is that you use AutoHotkey (Windows) or AutoKey (Linux). Both run in the background and accept arbitrary strings as trigger to run a command, which in this case is to send a special character to the clipboard and then paste it to whatever program is currently being used.

The example given has /delta as the trigger (including the forward slash). After typing those six characters, they are deleted and replaced with a δ.

Answer 8

Activating the Compose Key in GNOME 46

In GNOME 46, you can easily enable the Compose Key to type special characters. To activate it, follow these steps:

1. Open the Settings application.
2. Navigate to Keyboard.
3. Find the Special Characters Key section.
4. Enable the Compose Key and select your preferred key, such as the Right Alt or Menu key.

Once activated, you can use the Compose Key to input special characters. For example, pressing the Compose Key followed by o and c will produce the copyright symbol: ©.