Measure disk space of certain file types in aggregate

Question

I have some files across several folders:

/home/d/folder1/a.txt /home/d/folder1/b.txt /home/d/folder1/c.mov /home/d/folder2/a.txt /home/d/folder2/d.mov /home/d/folder2/folder3/f.txt 

How can I measure the grand total amount of disk space taken up by all the .txt files in /home/d/?

I know du will give me the total space of a given folder, and ls -l will give me the total space of individual files, but what if I want to add up all the txt files and just look at the space taken by all .txt files in one giant total for all .txt in /home/d/ including both folder1 and folder2 and their subfolders like folder3?

Answer 1

find folder1 folder2 -iname '*.txt' -print0 | du --files0-from - -c -s | tail -1

Answer 2

This will report disk space usage in bytes by extension:

find . -type f -printf "%f %s\n" |   awk '{       PARTSCOUNT=split( $1, FILEPARTS, "." );       EXTENSION=PARTSCOUNT == 1 ? "NULL" : FILEPARTS[PARTSCOUNT];       FILETYPE_MAP[EXTENSION]+=$2     }    END {      for( FILETYPE in FILETYPE_MAP ) {        print FILETYPE_MAP[FILETYPE], FILETYPE;       }    }' | sort -n 

Output:

3250 png 30334451 mov 57725092729 m4a 69460813270 3gp 79456825676 mp3 131208301755 mp4