How to check corrupt and duplicated fonts on Linux

command linefonts

I need to find software that can detect duplicate fonts out of a folder, and be able to tell if a font file is corrupted. Needs to be command line so I can script it for situations, although if you know of a GUI one that can take scripts or something of the sort that could possibly work as well.

Best Answer

I don't know how you could detect corrupt fonts but since font files are just files like any other, you can search through your directory and check for duplicate md5sums to find the duplicates.

This can be scripted fairly easily, for example, in Perl:

find /usr/share/fonts -type f -exec md5sum '{}' + | 
  perl -lane 'push @{$k{shift(@F)}, @F; 
              END{
                  map{ 
                     if($#{$k{$_}}>1){print; print for @{$k{$_}}} 
                     }keys(%k)
              }'

I created 4 duplicate fonts on my system and got this output:

/usr/share/fonts/truetype/mine/dup3.tiff
/usr/share/fonts/truetype/mine/dup1.iff
/usr/share/fonts/truetype/mine/dup2.tiff
/usr/share/fonts/truetype/mine/original.tiff

/usr/share/fonts/X11/Type1/encodings.dir
/usr/share/fonts/X11/75dpi/encodings.dir
/usr/share/fonts/X11/100dpi/encodings.dir

Still, if all you end up doing is finding duplicate files, there are far more sophisticated programs that can deal with this better and faster. See the answers here.

Related Solutions

Linux – How does Linux manage fonts

There are two mechanisms for fonts in X land: server-side and client-side.

The traditional way to render fonts is for the client to tell the server “render foo at position (x,y) in font F” (where a font specification includes a face, size, encoding and other attributes). Either the X server itself, or a specialized program called a font server, opens the font file to build the description of each glyph. The fonts can be bitmap or vector fonts, but the vector fonts are converted to bitmaps before rendering.

Most modern programs use client-side font rendering, often through xft and fontconfig. A new mechanism was needed because the server-side font rendering didn't support anti-aliasing.

Outside X (i.e. on a VGA console), there are VGA fonts, which are bitmap fonts of specific sizes. But compared to X11, no one uses the VGA console, so not much effort is spent on them.

In practice, you'll want to configure fonts in two ways:

For older-style programs: the font directories are listed via FontPath directives in xorg.conf and can be manipulated with xset fp commands by the user running X. If you install new fonts, you may need to run mkfontdir.
For newer-style programs, including all Gtk (Gnome, etc.) and Qt (KDE, etc.) programs: fonts are in the directories indicated by <dir> directives in /etc/fonts/fonts.conf, ~/.fonts.conf and a few other places. See the fontconfig documentation for more information. If you install new fonts, you may need to run fc-cache.

How to configure fonts on a remote X connection (XDMCP vs. ssh)

I believe XDMCP is using the fonts local to the Solaris system. When you SSH you're using fonts that are local, since in that scenario you're the X server and the Solaris box is the X client. You can use the command xlsfonts to see what fonts are accessible to you on a given system.

EDIT #1 - Font path

You can find out your system's font path using the command xset.

Example

$ xset q | sed -n '/Font/,/DPM/p'
Font Path:
  catalogue:/etc/X11/fontpath.d,built-ins
DPMS (Energy Star):

This path can include paths to local directories as well "paths" to other font servers. These will show up as port@host types of entries.