fmtutil man page

fmtutil — manage TeX formats, Metafont bases and Metapost mems, per-user
fmtutil-sys — manage TeX formats, Metafont bases and Metapost mems, system-wide
mktexfmt — create a TeX format, Metafont base, or Metapost mem


fmtutil [OPTION] ... [COMMAND]
fmtutil-sys [OPTION] ... [COMMAND]
mktexfmt FORMAT.fmt|BASE.base|MEM.mem|FMTNAME.EXT


fmtutil version svn36788 (2015-04-13 00:53:26 +0900)

Rebuild and manage TeX formats, Metafont bases and MetaPost mems.

If the command name ends in mktexfmt, only one format can be created. The only options supported are --help and --version, and the command line must consist of either a format name, with its extension, or a plain name that is passed as the argument to --byfmt (see below).  The full name of the generated file (if any) is written to stdout, and nothing else.

If not operating in mktexfmt mode, the command line can be more general, and multiple formats can be generated, as follows.


--cnffile FILE

read FILE instead of fmtutil.cnf (can be given multiple times, in which case all the files are used)


don't use engine-specific subdir of the fmtdir


exit successfully if no format is selected


exit successfully even if the required engine

is missing, if it is included in the list.


be silent


(not implemented, just for compatibility)


(not implemented, just for compatibility)


(not implemented, just for compatibility)



recreate all format files


create all missing format files


recreate only existing format files

--byengine ENGINENAME

(re)create formats using ENGINENAME


(re)create format for FORMATNAME

--byhyphen HYPHENFILE

(re)create formats that depend on HYPHENFILE

--enablefmt FORMATNAME

enable formatname in config file

--disablefmt FORMATNAME

disable formatname in config file


list (enabled and disabled) configurations, filtered to available formats


output the content of the config file

--showhyphen FORMATNAME

print name of hyphenfile for format FORMATNAME


show version information and exit


show this message and exit


Explanation of trees and files normally used:

If --cnffile is specified on the command line (possibly multiple times), its value(s) are used.  Otherwise, fmtutil reads all the fmtutil.cnf files found by running `kpsewhich -all fmtutil.cnf', in the order returned by kpsewhich.

In any case, if multiple fmtutil.cnf files are found, all the format definitions found in all the fmtutil.cnf files are merged.

Thus, if fmtutil.cnf files are present in all trees, and the default layout is used as shipped with TeX Live, the following files are read, in the given order.

    For fmtutil-sys:
    TEXMFSYSCONFIG $TEXLIVE/YYYY/texmf-config/web2c/fmtutil.cnf
    TEXMFSYSVAR    $TEXLIVE/YYYY/texmf-var/web2c/fmtutil.cnf
    TEXMFLOCAL     $TEXLIVE/texmf-local/web2c/fmtutil.cnf
    TEXMFDIST      $TEXLIVE/YYYY/texmf-dist/web2c/fmtutil.cnf
    For fmtutil:
    TEXMFCONFIG    $HOME/.texliveYYYY/texmf-config/web2c/fmtutil.cnf
    TEXMFVAR       $HOME/.texliveYYYY/texmf-var/web2c/fmtutil.cnf
    TEXMFHOME      $HOME/texmf/web2c/fmtutil.cnf
    TEXMFSYSCONFIG $TEXLIVE/YYYY/texmf-config/web2c/fmtutil.cnf
    TEXMFSYSVAR    $TEXLIVE/YYYY/texmf-var/web2c/fmtutil.cnf
    TEXMFLOCAL     $TEXLIVE/texmf-local/web2c/fmtutil.cnf
    TEXMFDIST      $TEXLIVE/YYYY/texmf-dist/web2c/fmtutil.cnf
    (where YYYY is the TeX Live release version).

According to the actions, fmtutil might write to one of the given files or create a new fmtutil.cnf, described further below.

Where changes are saved:

If config files are given on the command line, then the first one given will be used to save any changes from --enable or --disable. If the config files are taken from kpsewhich output, then the algorithm is more complex:

1) If $TEXMFCONFIG/web2c/fmtutil.cnf or $TEXMFHOME/web2c/fmtutil.cnf appears in the list of used files, then the one listed first by kpsewhich --all (equivalently, the one returned by kpsewhich fmtutil.cnf), is used.

2) If neither of the above two are present and changes are made, a new config file is created in $TEXMFCONFIG/web2c/fmtutil.cnf.

In general, the idea is that if a given config file is not writable, a higher-level one can be used.  That way, the distribution's settings can be overridden for system-wide using TEXMFLOCAL, and then system settings can be overridden again for a particular using using TEXMFHOME.

Resolving multiple definitions of a format:

If a format is defined in more than one config file, then the definition coming from the first-listed fmtutil.cnf is used.

Disabling formats:

fmtutil.cnf files with higher priority (listed earlier) can disable formats mentioned in lower priority (listed later) fmtutil.cnf files by writing, e.g.,

#! <fmtname> <enginename> <hyphen> <args>

in the higher-priority fmtutil.cnf file.

As an example, suppose you have want to disable the luajitlatex format. You can create the file $TEXMFCONFIG/web2c/fmtutil.cnf with the content

#! luajitlatex luajittex language.dat,language.dat.lua lualatex.ini

and call fmtutil.

fmtutil vs. fmtutil-sys (fmtutil --sys):

When fmtutil-sys is run or the command line option --sys is used, TEXMFSYSCONFIG and TEXMFSYSVAR are used instead of TEXMFCONFIG and TEXMFVAR, respectively.  This is the primary difference between fmtutil-sys and fmtutil.

Other locations may be used if you give them on the command line, or these trees don't exist, or you are not using the original TeX Live.

Reporting Bugs

Report bugs to:
TeX Live home page: <>

Referenced By


fmtutil-sys(1) and mktexfmt(1) are aliases of fmtutil(1).

April 2015 TeX Live User Commands