bash vs sh: моя запутаться

sh use deadbeef ololo
old: media-sound/deadbeef ape converter dts hotkeys psf src supereq alac curl shellexec cover cover-imlib2 mms lastfm wma zip pltbrowser m3u
new: /deadbeef ololo 

./use deadbeef ololo
old: media-sound/deadbeef ape converter dts hotkeys psf src supereq alac curl shellexec cover cover-imlib2 mms lastfm wma zip pltbrowser m3u
new: media-sound/deadbeef ape converter dts hotkeys psf src supereq alac curl shellexec cover cover-imlib2 mms lastfm wma zip pltbrowser m3u ololo

ls -lh /bin/sh 
lrwxrwxrwx 1 root 0 4 янв 24 06:00 /bin/sh -> bash

sh --version
GNU bash, version 4.2.45(1)-release (i686-pc-linux-gnu)
Copyright (C) 2011 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>

This is free software; you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

find_category(){
	source "/etc/make.conf" 2>/dev/null
	source "${PORT_ETC}/make.conf" 2>/dev/null
	[[ -z "${PORTDIR}" ]] && PORTDIR="/usr/portage"
	if [[ -n "$(eix -V 2>/dev/null)" ]];then
		PORTDIR_OVERLAY="$(eix --print PORTDIR_OVERLAY)"
	else
		export "$(grep "^PORTDIR_OVERLAY=" <<< "$(emerge --info 2>/dev/null)" | tr -d \")"
	fi
	for target in ${PORTDIR} ${PORTDIR_OVERLAY};do
		categories+="$(ls -d1 ${target}/{*-*,virtual} 2>/dev/null)"$'\n'
	done
	categories="$(sed '/^$/d' <<< "${categories}" 2>/dev/null)"
	while read line;do
		if [[ -d "${line}/${atom}" ]];then
			category+="${line##*/}"$'\n'
		fi
	done <<< "${categories}"
	echo "${category}"
}