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.Dd "December 25, 2002"
.Dt md 1
.Os
.Sh NAME
.Nm md
.Nd process raw dependency files produced by cpp -MD
.Sh SYNOPSIS
.Nm
.Op Fl d
.Op Fl f
.Op Fl m Ar makefile
.Op Fl u Ar makefile
.Op Fl o Ar outputfile
.Op Fl v
.Op Fl x
.Op Fl D Ar c|d|m|o|t|D
.Sh DESCRIPTION
The
.Nm
command basically does two things:
.Pp
Process the raw dependency files produced by the cpp -MD option.
There is one line in the file for every #include encountered, but
there are repeats and patterns like .../dir1/../dir2 that appear which
should reduce to .../dir2.
.Nm
canonicalizes and flushes repeats from the dependency list.
It also sorts the file names and "fills" them to a 78 character line.
.Pp
.Nm
also updates the makefile directly with the dependency information,
so the .d file can be thrown away (see
.Ar d
option).  This is done to save space.
.Nm
assumes that dependency information in the makefile is sorted by .o
file name and it procedes to merge in (add/or replace [as appropriate])
the new dependency lines that it has generated.
For time efficiency,
.Nm
assumes that any .d files it is given that were created
before the creation date of the "makefile" were processed
already.  It ignores them unless the force flag
.Op f
is given.
.Pp
.Sh FLAG SUMMARY
.Bl -tag -width indent
.It Fl D Ar c|D|d|m|o|t
Specify debugging option(s):
.Bl -tag -width indent
.It c
show file contents
.It D
show very low level debugging
.It d
show new dependency crunching
.It m
show generation of makefile
.It o
show files being opened
.It t
show time comparisons
.El
.It Fl d
Delete the .d file after it is processed
.It Fl f
Force an update of the dependencies in the makefile,
even if the makefile is more recent than the .n file.
(This implies that
.Nm
has been run already.)
.It Fl m Ar makefile
Specify the makefile to be upgraded.  The defaults are
.Ar makefile
and then
.Ar Makefile .
.It Fl o Ar outputfile
Specify an output file (other than a makefile) for the dependencies.
.It Fl u Ar makefile
Like
.Fl m ,
but the file will be created if necessary.
.It Fl v
Set the verbose flag.
.It Fl x
Expunge old dependency information from the makefile.
.El
.Sh SEE ALSO
.Xr make 1
.Sh BUGS
Old, possibly not used by anyone.
.Sh HISTORY
The
.Nm
utility was written by Robert V. Baron at Carnegie-Mellon University.