printing comma-separated integer size of directory and contents - bash

Question

The following will print out the size in bytes of a directory and its contents:
ls -lR | grep -v '^d' | awk '{bytes += $5} END {print "Total bytes: " bytes}'
The output looks like this:
Total bytes: 1088328265
How can I most-simply modify my command so that the output has comma-separated numbers, like this:
Total bytes: 1,088,328,265

Answer 1

$ awk 'BEGIN{printf "Total bytes: %\047d\n", 1088328265}'
Total bytes: 1,088,328,265
So puting aside the usual advice to not parse the output of ls and getting rid of the grep since you never need grep when you're using awk, we can make your whole command:
ls -lR | awk '!/^d/{bytes += $5} END{printf "Total bytes: %\047d\n", bytes}'
\047 is how to represent a single-quote in a single-quote-delimited awk script and then from the GNU awk manual:
A single quote or apostrophe character is a POSIX extension to ISO C. It indicates that the integer part of a floating-point value, or the entire part of an integer decimal value, should have a thousands-separator character in it. This only works in locales that support such characters. For example:
$ cat thousands.awk Show source program
-| BEGIN { printf "%'d\n", 1234567 }
$ LC_ALL=C gawk -f thousands.awk
-| 1234567 Results in "C" locale
$ LC_ALL=en_US.UTF-8 gawk -f thousands.awk
-| 1,234,567 Results in US English UTF locale
For more information about locales and internationalization issues, see Locales.

Answer 2

Using Perl instead of awk:
perl -lane '$bytes += $F[4];
END { substr $bytes, -3 * $_, 0, ","
for reverse 1 .. (length($bytes)-1)/3;
print "Total bytes: $bytes"}'
-l removes newlines from input and adds them to prints
-n reads the input line by line
-a splits the input on whitespace into the #F array
substr inserts spaces to each position; we use negative positions which count from the right, but we start from the leftmost position so the numbers don't change as we add the commas