Numbering files

main.sh

#!/bin/sh

prefix="__"

usage_error ()
{
	echo "$0: $*" >&2
	print_usage >&2
	exit 2
}
print_usage ()
{
	cat <<END
Usage:
  numbering_files.sh [--prefix=PREFIX] PATH
END
}

while test $# -gt 0; do
	case $1 in
	--prefix) prefix=$2; shift;;
	--) shift; break;;
	-*) usage_error "invalid option: '$1'";;
	*) break;;
	esac
	shift
done

target_path=${1:-$(pwd)}

find ${target_path} ! -name '*.DS_Store' -type f -mindepth 1 |\
# natural sort order
sort -Vk1,1 |\
# Use \0(Null character) as the field delimiter.
# FS is not space.
awk -v FS='\36' '{printf("%s%c",$1,0);}' |\
# $f -> filename
# $d -> directory name
# $e -> extension
# \36(oct) -> Record Separator(RS)
xargs -0 -L1 -I@ sh -c 'f="@";d=$(dirname "${f}");e=${f##*.}; printf "%s\36%s\36%s\n" "${f}" "${d}" "${e}"' |\
# \47(oct) -> '
awk -v PREFIX=${prefix} -F$'\36' '{c=sprintf("mv -nv \47%s\47 \47%s/%s%s.%s\47",$1,$2,PREFIX,NR,$3);system(c)close(c);}'