command: \*[]
meaning: String with arbitrary length. See also @xr{\*x}, @xr{\*(xy}, and @xr{.ds}
reference: 


command: .ti
meaning: Temporary indent

command: .nf
meaning: No fill (do not join lines); see also @xr{.fi}.

command: .fi
meaning: Fill (join lines); see also @xr{.nf}.

command: \nx
meaning: Value of number register x

command: \n(xx
meaning: Value of number register xx

command: .nr R N
meaning: Set value of number register R to N

command: .de xx yy
%%meaning: 

Define a macro. If yy is present then the definition ends at .yy, otherwise it ends at "..". See also @xr{..}.

%%

command: .Ms
meaning: Mathematical symbol

command: .yr
meaning: Years since 1900

command: .mso name
meaning: Include macro package name. See also @xr{.so}.

command: .ds abc xyz 
%%meaning: 
Define string abc to have the value xyz; expland with @xr{\*x} or @xr{\*(xy}.
See also @xr{.as} (append string).
%%

command: \*x
meaning: String x defined by @xr{.ds}

command: \*(xy
meaning: String xy defined by @xr{.ds}

command: .so file
meaning: Include "file". See also @xr{.mso}.

command: \ followed by new line
meaning: Line continuation marker.

command: .ft R
meaning: Font change

command: \\$n
meaning: Macro argument n, e.g. \\$1 is the first macro argument.

command: ..
meaning: End of macro. See @xr{.de}.

command: .if
meaning: If statement; see also if / else using @xr{.ie} and @xr{.el}.

command: \(co
meaning: Copyright mark, ©

command: \(*
meaning: Greek character conversion, e.g. \(*a gives α

command: .ps
meaning: Point size

command: .tm message
meaning: Terminal message; print message on the terminal.

command: .ie
meaning: If / else if part; see also @xr{.el} and @xr{.if}.

command: .el
meaning: If / else else part; see also @xr{.ie} and @xr{.if}.

command: .af R c
meaning: Assign format c to register R. See also @xr{.nr}.

command: .nx filename
%%meaning:
Switch to file filename, do not return to current file. See also @xr{.so}.
%%

command: .cf filename
%%meaning:
Copy file filename to output, unprocessed.
%%

command: .na
%%meaning:
No adjust. Ragged right margin.
%%

command: .Ss
%%meaning:
@man "Subsection".
%%

command: .Sh
%%meaning:
@man "Section heading"
%%

command: .nop anything
meaning: Always execute "anything". (nop means "no operation".)

command: .ec
meaning: Reset escape character to \

command: .Dt title
meaning: @man Title for BSD manual pages. See also @xr{.Dd}, @xr{.TH}.

command: .Dd
meaning: @man Date for BSD manual pages. See also @xr{.Dt}, @xr{.TH}.

command: .TH title section date source manual
meaning: @man Title for GNU manual pages. See also @xr{.Dd}, @xr{.Dt} for the BSD equivalents.

command: .PP
meaning: @man New paragraph

command: .Xr page section
meaning: @man Cross-reference to manual page "page" in section "section" of the manual.

command: .Fn function
meaning: @man Function

command: .als alias object
meaning: Alias for request, string, macro, or diversion object.

command: \[la]
meaning: <
reference: groff_char.7

command: \[ra]
meaning: >
reference: groff_char.7

command: .shift n
meaning: Shift the arguments by n positions
reference: groff.7

command: \$@
%%meaning:
In a macro or string, the concatenation of all the arguments with each surrounded by double quotes, and separated by spaces.
%%
reference: groff.y

command: .$
%%meaning:

Number of arguments available at the current level.

%%
reference: troff.pdf, groff.7

command: .nh
meaning: No hyphenation; see also @xr{.hy}.

command: .hy
meaning: Hyphenation; see also @xr{.nh}.

command: .Sm on / off
meaning: @man Space mode on / off; do or do not put spaces between arguments
reference: groff_tmac

command: \~
meaning: Non-breaking space

command: .as name string
meaning: Append string to string name (append version of @xr{.ds}).

command: \&
meaning: Non-printing zero-width character.

command: \s
meaning: Point-size change function
reference: troff.pdf

command: .f
meaning: Predefined read-only register containing number of current font.

command: .return
meaning: @groff return from a macro. See also @xr{.de}.
reference: groff manual

command: .g
meaning: @groff register which is true for GNU troff (groff)

command: .x
meaning: Reserved version-dependent register (contains major version of groff)

command: .y
meaning: Reserved version-dependent register (contains minor version of groff)

command: .F
meaning: Current input file name

command: .ec c
meaning: Set escape character to "c". If c is empty, set it to \.

command: .eo
meaning: Turn off escape mechanism

command: "
meaning: In a string definition, marker for whitespace at the beginning of the string.

command: .Os
meaning: @man Macro which expands to the name of the operating system.

command: .Nd
meaning: @man Emphasize following text (used in SYNOPSIS section).

command: .Lb
meaning: @man Macro which expands to the name of a library.


command: \c
meaning: Connect to next input text (not sure what this means?)

command: \f[CO]
meaning: Courier font
reference: http://swtch.com/usr/local/plan9/troff/font/devutf/

command: \f[CB]
meaning: Courier-Bold font
reference: http://swtch.com/usr/local/plan9/troff/font/devutf/


command: .It
meaning: @man List item

command: .Dq
meaning: @man Double quotes around what follows

command: .Sq
meaning: @man Single quotes

command: .Cm commands
meaning: @man Command (like a flag without - in front)

command: .c
meaning: Number of lines read from current input file.


command: $0
meaning: Name of the macro executing

command: .So
meaning: 

command: .Sc
meaning: 

command: .Bf
meaning: Begin a font, either emphasis, symbolic (bold) or literal (monospace). See also @xr{.Ef}.

command: .Ef
meaning: End a font started with @xr{.Bf}

command: .Rv std function1 function2
%%meaning:

Display text stating the standard return values for the
functions. Always takes std after the .Rv.


%%

command: .Bk
meaning: Begin keep. See also @xr{.Ek}.
reference: groff_mdoc

command: .Ek
meaning: End keep. See also @xr{.Bk}.
reference: groff_mdoc

command: .Bd
%%meaning: 
Begin display. This can begin indented text, preformatted text like source code, or filled text depending on the argument. The section ends with @xr{.Ed}.
%%

command: .Ed
meaning: End of a @xr{.Bd} block.

command: .Bd -literal
%%meaning:
Start of preformatted text.
%%

command: .Nm
meaning: Name of command.

command: .Dl
meaning: Literal line

command: .Xo
meaning: @man Extend the current line of arguments until @xr{.Xc} is seen.
reference: groff_tmac


command: .Xc
meaning: End of an @xr{.Xo} block.


command: .TS
meaning: Start of a table (see also @xr{.TE}).

command: .TE
meaning: End of a table (see also @xr{.TS}).

command: .EQ
meaning: Start of equation

command: .URL
meaning: GNU www.mdoc extension

command: .MTO
meaning: GNU mailto www extension

command: \$*
meaning: Unknown

command: .ie n
meaning: If in "nroff" mode (terminal output)

command: .ie t
meaning: If in "troff" mode (print output)



command: .TP
meaning: Indented paragraph with label.


command: .Li
meaning: Literal text

command: .Pa
meaning: Unknown

command: .In
meaning: @man An "include" file for a C program.

command: .Ar
meaning: @man An argument. This becomes "file ..." by default.

command: .Ta
%%meaning:
@man A tab in a table. The literal tab character is also used. If you
want to go insane, try writing a troff processor.
%%


command: .Bl
meaning: @man Begin a list. See also @xr{.El} for ending.

command: .El
meaning: @man End a list. See also @xr{.Bl} for ending.

command: .St
meaning: @man Standards of various kinds.

command: .Pf
meaning: @man Unknown

command: .Ns
meaning: @man No spaces, used between things to not add spaces there.

command: .BR
%%meaning:
Causes text on the same line to appear alternately in bold face and
roman.  The text must be on the same line as the macro call. This is
often used for a manual page, like
<pre class='perl-code'>
.BR stdio (3)
</pre>
See also @xr{.IR}.
%%

command: .IR
%%meaning:
Causes text on the same line to appear alternately in italic and
roman.  The text must be on the same line as the macro call.  This is
often used for a manual page, like
<pre class='perl-code'>
.IR stdio (3)
</pre>
See also @xr{.BR}.
%%

command: .IP
%%meaning:
Indented paragraph
%%

command: .Fo
%%meaning:
@man
Function open, used after the function's type and before the name of
the function.
%%

command: .Ft
%%meaning:
@man
Function type, like int or char.
%%

command: .Fa
%%meaning:
@man
Function argument
%%

command: .Fd
%%meaning: 

@man
Function declaration in the synopsis section.

%%