# BSD 2.11 - man page for eqn (bsd section 1)

EQN(1) General Commands Manual EQN(1)delim $$eqn, neqn, checkeq - typeset mathematicsNAMEeqn [SYNOPSIS] [-dxy] [-pn] [-sn] [ file ] ... checkeq [ file ] ...-fnEqn is a troff(1) preprocessor for typesetting mathematics on a Graphic Systems phototypesetter, neqn on terminals. Usage is almost always eqn file ... | troff neqn file ... | nroff If no files are specified, these programs read from the standard input. A line beginning with `.EQ' marks the start of an equation; the end of an equation is marked by a line beginning with `.EN'. Neither of these lines is altered, so they may be defined in macro packages to get centering, numbering, etc. It is also possible to set two characters as `delimiters'; subsequent text between delimiters is also treated as eqn input. Delimiters may be set to characters x and y with the command-line argumentDESCRIPTIONor (more commonly) with `delim xy' between .EQ and .EN. The left and right delimiters may be identical. Delimiters are turned off by `delim off'. All text that is neither between delimiters nor between .EQ and .EN is passed through untouched. The program checkeq reports missing or unbalanced delimiters and .EQ/.EN pairs. Tokens within eqn are separated by spaces, tabs, newlines, braces, double quotes, tildes or circumflexes. Braces {} are used for grouping; generally speaking, anywhere a single character like x could appear, a complicated construction enclosed in braces may be used instead. Tilde ~ represents a full space in the output, circumflex ^ half as much. Subscripts and superscripts are produced with the keywords sub and sup. Thus x sub i makes $x sub i$, a sub i sup 2 produces $a sub i sup 2$, and e sup {x sup 2 + y sup 2} gives $e sup {x sup 2 + y sup 2}$. Fractions are made with over: a over b yields $a over b$. sqrt makes square roots: 1 over sqrt {ax sup 2 +bx+c} results in $1 over sqrt {ax sup 2 +bx+c}$ . The keywords from and to introduce lower and upper limits on arbitrary things: $lim from {n-> inf} sum from 0 to n x sub i$ is made with lim from {n-> inf } sum from 0 to n x sub i. Left and right brackets, braces, etc., of the right height are made with left and right: left [ x sup 2 + y sup 2 over alpha right ] ~=~1 produces $left [ x sup 2 + y sup 2 over alpha right ] ~=~1$. The right clause is optional. Legal characters after left and right are braces, brackets, bars, c and f for ceiling and floor, and "" for nothing at all (useful for a right-side-only bracket). Vertical piles of things are made with pile, lpile, cpile, and rpile: pile {a above b above c} produces $pile {a above b above c}$. There can be an arbitrary number of elements in a pile. lpile left-justifies, pile and cpile center, with different vertical spacing, and rpile right justifies. Matrices are made with matrix: matrix { lcol { x sub i above y sub 2 } ccol { 1 above 2 } } produces $matrix { lcol { x sub i above y sub 2 } ccol { 1 above 2 } }$. In addition, there is rcol for a right-justified column. Diacritical marks are made with dot, dotdot, hat, tilde, bar, vec, dyad, and under: x dot = f(t) bar is $x dot = f(t) bar$, y dotdot bar ~=~ n under is $y dotdot bar ~=~ n under$, and x vec ~=~ y dyad is $x vec ~=~ y dyad$. Sizes and font can be changed with size n or size +-n, roman, italic, bold, and font n. Size and fonts can be changed globally in a docu- ment by gsize n and gfont n, or by the command-line arguments-dxyand-snNormally subscripts and superscripts are reduced by 3 point sizes from the previous size; this may be changed by the command-line argument-fn.Successive display arguments can be lined up. Place mark before the desired lineup point in the first equation; place lineup at the place that is to line up vertically in subsequent equations. Shorthands may be defined or existing keywords redefined with define: define thing % replacement % defines a new token called thing which will be replaced by replacement whenever it appears thereafter. The % may be any character that does not occur in replacement. Keywords like sum ( sum ) int ( int ) inf ( inf ) and shorthands like >= (>=) -> (->), and != ( != ) are recognized. Greek letters are spelled out in the desired case, as in alpha or GAMMA. Mathematical words like sin, cos, log are made Roman automatically. Troff(1) four- character escapes like \(bs () can be used anywhere. Strings enclosed in double quotes "..." are passed through untouched; this permits keywords to be entered as text, and can be used to communicate with troff when all else fails.-pn.troff(1), tbl(1), ms(7), eqnchar(7) B. W. Kernighan and L. L. Cherry, Typesetting Mathematics--User's Guide J. F. Ossanna, NROFF/TROFF User's ManualSEE ALSOTo embolden digits, parens, etc., it is necessary to quote them, as in `bold "12.3"'.BUGS7th EditionMay 9, 1986 EQN(1)