Find the total size of certain files within a directory branch

23

The ultimate answer is:

{ find <DIR> -type f -name "*.<EXT>" -printf "%s+"; echo 0; } | bc

and even faster version, not limited by RAM, but that requires GNU AWK with bignum support:

find <DIR> -type f -name "*.<EXT>" -printf "%s\n" | gawk -M '{t+=$1}END{print t}'

This version has the following features:

• all capabilities of find to specify the files you’re looking for
• supports millions of files
  • other answers here are limited by the maximum length of the argument list
• spawns only 3 simple processes with a minimal pipe throughput
  • many answers here spawn C+N processes, where C is some constant and N is the number of files
• doesn’t bother with string manipulation
  • this version doesn’t do any grepping, or regexing
  • well, find does a simple wildcard matching of filenames
• optionally formats the sum into a human-readable form (eg. 5.5K, 176.7M, …)
  • to do that append | numfmt --to=si