Metafont reads the program in the specified files and outputs font rasters (in gf format) and font metrics (in tfm format). The Metafont language is described in The Metafontbook.

Like TeX, Metafont is normally used with a large body of precompiled macros, and font generation in particular requires the support of several macro files. This version of Metafont looks at its command line to see what name it was called under. Both inimf and virmf are symlinks to the mf executable. When called as inimf (or when the --ini option is given) it can be used to precompile macros into a .base file. When called as virmf it will use the plain base. When called under any other name, Metafont will use that name as the name of the base to use. For example, when called as mf the mf base is used, which is identical to the plain base. Other bases than plain are rarely used.

The commands given on the command line to the Metafont program are passed to it as the first input line. (But it is often easier to type extended arguments as the first input line, since UNIX shells tend to gobble up or misinterpret Metafont's favorite symbols, like semicolons, unless you quote them.) As described in The Metafontbook, that first line should begin with a filename, a \controlsequence, or a &basename.

The normal usage is to say

mf '\mode=<printengine>; [mag=magstep(n);]' input font

to start processing font.mf. The single quotes are the best way of keeping the Unix shell from misinterpreting the semicolons and from removing the \ character, which is needed here to keep Metafont from thinking that you want to produce a font called mode. (Or you can just say mf and give the other stuff on the next line, without quotes.) Other control sequences, such as batchmode (for silent operation) can also appear. The name font will be the ``jobname'', and is used in forming output file names. If Metafont doesn't get a file name in the first line, the jobname is mfput. The default extension, .mf, can be overridden by specifying an extension explicitly.

A log of error messages goes into the file jobname.log. The output files are jobname.tfm and jobname.<number>gf, where <number> depends on the resolution and magnification of the font. The mode in this example is shown generically as <printengine>, a symbolic term for which the name of an actual device or, most commonly, the name localfont (see below) must be substituted. If the mode is not specified or is not valid for your site, Metafont will default to proof mode which produces large character images for use in font design and refinement. Proof mode can be recognized by the suffix .2602gf after the jobname. Examples of proof mode output can be found in Computer Modern Typefaces (Volume E of Computers and Typesetting). The system of magsteps is identical to the system used by TeX, with values generally in the range 0.5, 1.0, 2.0, 3.0, 4.0 and 5.0. A listing of gf numbers for 118-dpi, 240-dpi and 300-dpi fonts is shown below.

MAGSTEP118 dpi240 dpi300 dpi

mag=magstep(0)118240300

mag=magstep(0.5)129263329

mag=magstep(1)142288360

mag=magstep(2)170346432

mag=magstep(3)204415518

mag=magstep(4)245498622

mag=magstep(5)294597746

Magnification can also be specified not as a magstep but as an
arbitrary value, such as 1.315, to create special character sizes.

Before font production can begin, it is necessary to set up the
appropriate base files.  The minimum set of components for font
production for a given print-engine is the
plain.mf
macro file
and the local
mode_def
file.  The macros in
plain.mf
can be
studied in an appendix to the
Metafontbook;
they were developed by Donald E. Knuth, and this file should never be
altered except when it is officially upgraded.
Each
mode_def
specification helps adapt fonts to a particular print-engine.
There is a regular discussion of
mode_defs
in
TUGboat,
the journal of the
TeX
Users Group.
The local ones in use on this computer should be in
modes.mf.

The
e
response to Metafont's error-recovery mode invokes the
system default
editor at the erroneous line of the source file.
There is an environment variable, MFEDIT,
that overrides the default editor.
It should contain a string with "%s" indicating where the
filename goes and "%d" indicating where the decimal linenumber (if any) goes.
For example, an MFEDIT string for the
vi
editor can be set with the
csh
command

setenv MFEDIT "vi +%d %s"

A convenient file in the library is
null.mf,
containing nothing.
When
mf
can't find the file it thinks you want to input, it keeps
asking you for another file name; responding `null' gets you out
of the loop if you don't want to input anything.

On some systems, there are two Metafont binaries, mf and mfw. On those systems the mfw binary supports graphics, while the mf binary does not.

--base base

Use base as the name of the base to be used, instead of the name by which Metafont was called or a %& line.

--file-line-error-style

Print error messages in the form file:line:error which is similar to the way many compilers format them.

--help

Print help message and exit.

--ini

Be inimf, for dumping bases; this is implicitly true if the program is called as inimf.

--interaction mode

Sets the interaction mode. The mode can be one of batchmode, nonstopmode, scrollmode, and errorstopmode. The meaning of these modes is the same as that of the corresponding commands.

--jobname name

Use name for the job name, instead of deriving it from the name of the input file.

--kpathsea-debug bitmask

Sets path searching debugging flags according to the bitmask. See the Kpathsea manual for details.

--maketex fmt

Enable mktexfmt, where fmt must be mf.

--no-maketex fmt

Disable mktexfmt, where fmt must be mf.

--parse-first-line

If the first line of the main input file begins with %& parse it to look for a dump name or a --translate-file option.

--progname name

Pretend to be program name. This affects both the format used and the search paths.

--recorder

Enable the filename recorder. This leaves a trace of the files opened for input and output in a file with extension .fls.

--translate-file tcxname

Use the tcxname translation table.

--version

Print version information and exit.

If the environment variable TEXMFOUTPUT is set, Metafont attempts to put its output files in it, if they cannot be put in the current directory. Again, see tex(1).

MFINPUTS

Search path for input and openin files.

MFEDIT

Command template for switching to editor.

MFTERM

Determines the online graphics display. If MFTERM is not set, and DISPLAY is set, the Metafont window support for X is used. (DISPLAY must be set to a valid X server specification, as usual.) If neither MFTERM nor DISPLAY is set, TERM is used to guess the window support to use.

gftopk

Takes a gf file and produces a more tightly packed pk font file.

gftodvi

Produces proof sheets for fonts.

gftype

Displays the contents of a gf file in mnemonics and/or images.

pktype

Mnemonically displays the contents of a pk file.

mft

Formats a source file as shown in Computer Modern Typefaces.

mf.pool

Encoded text of Metafont's messages.

*.base

Predigested Metafont base files.

$TEXMFMAIN/metafont/base/plain.mf

The standard base.

$TEXMFMAIN/metafont/misc/modes.mf

The file of mode_defs for your site's various printers