Guide to LaTeX (4th Edition) (Tools and Techniques

562 Appendix H. Command Summary
\newcommand{com name}[narg][opt]{def } . . . . . . . (8.3) – 185
Defines a user command with the name \com name to be def. The
first optional argument narg ≤ 9 specifies how many variable arguments
the command is to have, which appear in the def as the
replacement characters #1 to #narg. If the second optional argument
is present, the first argument of the new command is optional,
and takes on the value opt if it is not explicitly given.
\newcommand*{com name}[narg][opt]{def } . . . . . . (D.2.6) – 445
The same as \newcommand except that the arguments to \com name
must be ‘short’, not containing any new paragraphs.
\newcounter{counter name}[in counter] . . . . . . . (8.1.2) – 182
Establishes a new counter with the name counter name. The optional
argument in counter is the name of an existing counter which, when
incremented, resets the new counter to zero; that is, the new counter
is a sub-counter of in counter.
\newenvironment{env name}[narg][opt]{beg def }{end def }
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (8.4) – 195
Defines a user environment with the name env name which has the
\begin definition beg def and the \end definition end def. The
optional argument narg ≤ 9 specifies how many variable arguments
the environment is to have, which appear in the beg def as the
replacement characters #1 to #narg. If the second optional argument
is present, the first argument of the \begin command is optional,
and takes on the value opt if it is not explicitly given.
\newenvironment*{env name}[narg][opt]{beg def }{end def }
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . (D.2.6) – 445
The same as \newenvironment except that the arguments to
\begin{env name} must be ‘short’, not containing any new paragraphs.
\newfont{\font cmd}{\font name scaled size} . . . . . (4.1.5) – 66
Establishes the relation between the font file name file name magnified
by the scaling factor size and a font selection command
\font cmd. After \font cmd has been called, \baselineskip, the
interline spacing, still has its previous value.
\newlength{\length cmd} . . . . . . . . . . . . . . . . (8.2) – 185
Creates a new length command with the name \length cmd and
initializes it to 0 pt. New values may be assigned as for all length
commands with the \setlength command:
\setlength{\length cmd}{length}
The quantity length must have units (cm, pt, etc.) and may be a
rubber length.