16.24 Counting Files by Types

I use awk (33.11 ) a lot. One of my favorite features of awk is its associative arrays. This means awk can use anything as an index into an array. In the next example, I use the output of the file (25.8 ) command as the index into an array to count how many files there are of each type:

${*-.}
 xargs
 

#!/bin/sh
# usage: count_types [directory ...]
# Counts how many files there are of each type
# Original by Bruce Barnett
# Updated version by yu@math.duke.edu (Yunliang Yu)
find ${*-.} -type f -print | xargs file |
awk '{
        $1=NULL;
        t[$0]++;
} 
END {
        for (i in t) printf("%d\t%s\n", t[i], i);
}' | sort -nr   # Sort the result numerically, in reverse

The output of this might look like:

38  ascii text
32  English text
20  c program text
17  sparc executable not stripped
12  compressed data block compressed 16 bits
8   executable shell script
1   sparc demand paged dynamically linked executable
1   executable /bin/make script