我的设置：TeX Live，版本 2014.20141024-2（与 Debian 8 Jessie 一起打包）
保存默认 PL：
$ tftopl cmr10 > cmr10.pl.old
生成新的 TFM：
$ mktextfm cmr10
mktextfm: Running mf-nowin -progname=mf \mode:=ljfour; mag:=1; nonstopmode; input cmr10
This is METAFONT, Version 2.7182818 (TeX Live 2015/dev/Debian) (preloaded base=mf)
(/usr/share/texlive/texmf-dist/fonts/source/public/cm/cmr10.mf
(/usr/share/texlive/texmf-dist/fonts/source/public/cm/cmbase.mf)
(/usr/share/texlive/texmf-dist/fonts/source/public/cm/roman.mf
(/usr/share/texlive/texmf-dist/fonts/source/public/cm/romanu.mf [65] [66]
[67] [68] [69] [70] [71] [72] [73] [74] [75] [76] [77] [78] [79] [80] [81]
[82] [83] [84] [85] [86] [87] [88] [89] [90])
(/usr/share/texlive/texmf-dist/fonts/source/public/cm/romanl.mf [97] [98]
[99] [100] [101] [102] [103] [104] [105] [106] [107] [108] [109] [110] [111]
[112] [113] [114] [115] [116] [117] [118] [119] [120] [121] [122])
(/usr/share/texlive/texmf-dist/fonts/source/public/cm/greeku.mf [0] [1]
[2] [3] [4] [5] [6] [7] [8] [9] [10])
(/usr/share/texlive/texmf-dist/fonts/source/public/cm/romand.mf [48] [49]
[50] [51] [52] [53] [54] [55] [56] [57])
(/usr/share/texlive/texmf-dist/fonts/source/public/cm/romanp.mf [36] [38]
[63] [62]) (/usr/share/texlive/texmf-dist/fonts/source/public/cm/romspl.mf
[16] [17] [25] [26] [27] [28])
(/usr/share/texlive/texmf-dist/fonts/source/public/cm/romspu.mf [29] [30]
[31]) (/usr/share/texlive/texmf-dist/fonts/source/public/cm/punct.mf [33]
[60] [35] [37] [39] [40] [41] [42] [43] [44] [46] [47] [58] [59] [61] [64]
[91] [93] [96]) (/usr/share/texlive/texmf-dist/fonts/source/public/cm/accent.mf
[18] [19] [20] [21] [22] [23] [24] [32] [94] [95] [125] [126] [127])
(/usr/share/texlive/texmf-dist/fonts/source/public/cm/romlig.mf [11] [12]
[13] [14] [15]) (/usr/share/texlive/texmf-dist/fonts/source/public/cm/comlig.mf
[34] [45] [92] [123] [124]) ) )
Font metrics written on cmr10.tfm.
Output written on cmr10.600gf (128 characters, 24096 bytes).
Transcript written on cmr10.log.
mktextfm: /usr/local/share/texmf/fonts/tfm/public/cm/cmr10.tfm: successfully generated.
/usr/local/share/texmf/fonts/tfm/public/cm/cmr10.tfm
首先：如果已经存在 TFM，mktextfm 不应生成新的 TFM。其次：比较旧 PL 和新 PL。它们本应相同，但实际上却不同。为什么？
$ tftopl cmr10 | diff -u cmr10.pl.old -
--- cmr10.pl.old
+++ -
@@ -1,6 +1,3 @@
-(FAMILY CMR)
-(FACE O 352)
-(CODINGSCHEME TEX TEXT)
(DESIGNSIZE R 10.0)
(COMMENT DESIGNSIZE IS IN POINTS)
(COMMENT OTHER SIZES ARE MULTIPLES OF DESIGNSIZE)