keyboard – how to type characters

Keyboards are idiosyncratic. It should be obvious how to type ordinary ASCII characters, backspace, tab, escape, and newline. In Plan 9, the key labeled Return or Enter generates a newline (0x0A); if there is a key labeled Line Feed, it generates a carriage return (0x0D); Plan 9 eschews CRLFs. All control characters are typed in the usual way; in particular, control-J is a line feed and control-M a carriage return.
The down arrow, used by 9term(1), acme(1), and sam(1), causes windows to scroll forward. The up arrow scrolls backward.
Characters in Plan 9 are runes (see utf(7)). Any rune can be typed using a compose key followed by several other keys. The compose key is also generally near the lower right of the main key area: the NUM PAD key on the Gnot, the Alternate key on the Next, the Compose key on the SLC, the Option key on the Magnum, and either Alt key on the PC. To type a single rune with the value specified by a given four-digit hexadecimal number, type the compose key, then a capital X, and then the four hexadecimal digits (decimal digits and a to f). For a longer rune, type X twice followed by five digits, or type X three times followed by six digits. There are shorthands for many characters, comprising the compose key followed by a two- or three-character sequence. The full list is too long to repeat here, but is contained in the file /usr/local/plan9/lib/keyboard in a format suitable for grep(1) or look(1). To add a sequence, edit that file and then rebuild devdraw(1).
There are several rules guiding the design of the sequences, as illustrated by the following examples.
A repeated symbol gives a variant of that symbol, e.g., ?? yields ¿.
ASCII digraphs for mathematical operators give the corresponding operator, e.g., <= yields ≤.
Two letters give the corresponding ligature, e.g., AE yields Æ.
Mathematical and other symbols are given by abbreviations for their names, e.g., pg yields ¶.
Chess pieces are given by a w or b followed by a letter for the piece (k for king, q for queen, r for rook, n for knight, b for bishop, or p for pawn), e.g., wk for a white king.
Greek letters are given by an asterisk followed by a corresponding latin letter, e.g., *d yields δ.
Cyrillic letters are given by an at sign followed by a corresponding latin letter or letters, e.g., @ya yields я.
Script letters are given by a dollar sign followed by the corresponding regular letter, e.g., $F yields ℱ.
A digraph of a symbol followed by a letter gives the letter with an accent that looks like the symbol, e.g., ,c yields ç.
Two digits give the fraction with that numerator and denominator, e.g., 12 yields ½.
The letter s followed by a character gives that character as a superscript, e.g., s1 yields ⁱ. These characters are taken from the Unicode block 0x2070; the 1, 2, and 3 superscripts in the Latin-1 block are available by using a capital S instead of s.
Sometimes a pair of characters give a symbol related to the superimposition of the characters, e.g., cO yields ©.
A mnemonic letter followed by $ gives a currency symbol, e.g., l$ yields £.
Note the difference between ß (ss) and µ (micron) and the Greek β and μ.

Under X Windows, both the Alt key and the “Multi key” can begin a compose sequence in a Plan 9 program.
It is also possible to configure X Windows to use the same keystroke mappings as the Plan 9 programs. First, generate an XCompose sequence list by using mklatinkbd:
mklatinkbd −x $PLAN9/lib/keyboard >$HOME/.XCompose
Second, configure a “Multi key” by running
xmodmap −e 'keysym Super_L = Multi_key'
(The name Super_L typically denotes the Windows key on recent keyboards.)
Third, set these environment variables so that GTK- and QT-based programs will use the compose sequences:
export GTK_IM_MODULE=xim
export QT_IM_MODULE=xim
Finally, start a new GTK- or QT-based program:
gnome−terminal &
In that terminal, typing the key sequence ‘Windows * a’ should be interpreted as the Greek letter α.
If using the GNOME Window Manager, put the xmodmap and export commands into the file $HOME/.gnomerc to run them automatically at startup.

sorted table of characters and keyboard sequences

intro(1), ascii(1), tcs(1), 9term(1), acme(1), sam(1), utf(7)

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