sloc

SLOC - Source Lines Of Code

sloc is a simple, do-one-thing-well program to calculate code statistics: the number of lines in a project, and how much of that is code versus comment.

$ sloc ~/misc/opt/go
    Language  Files    Code  Comment  Blank   Total
       Total   2808  512357    87177  67791  667325
          Go   2048  295054    62020  37973  395047
           C    474  166702    22330  21849  210881
        HTML     58   25627      183   4241   30051
    Assembly    131    9974      161   1491   11626
        YACC      6    5245      363    449    6057
      Python      6    2940      789    495    4224
  JavaScript      6    2526      496    585    3607
         XML      9     974       15     90    1079
       Shell      9     905      380    155    1440
         CSS      6     899       24    119    1042
        Perl      9     854      159    135    1148
        Bash     13     483      151    122     756
        Make     33     174      106     87     367

sloc cannot understand gitignore or hgignore, nor can it distinguish between "real" source and auto-generated files, so for best results, run it on a fresh repository with no compilation done.

You can generate JSON output with the -json flag, if that's easy to parse in the programming/scripting language of your choice.