diff --git a/init.d/consolefont.in b/init.d/consolefont.in
index cd0c8de8..f83b0036 100644
--- a/init.d/consolefont.in
+++ b/init.d/consolefont.in
@@ -49,7 +49,7 @@ start()
 			retval=1
 			break
 		fi
-		x=$(($x + 1))
+		: $(( x += 1 ))
 	done
 	eend $retval
 
diff --git a/init.d/hwclock.in b/init.d/hwclock.in
index b79ff7c9..cfb25ae1 100644
--- a/init.d/hwclock.in
+++ b/init.d/hwclock.in
@@ -85,7 +85,7 @@ start()
 
 	if [ -e /etc/adjtime ] && yesno $clock_adjfile; then
 		_hwclock --adjust $utc_cmd
-		retval=$(($retval + $?))
+		: $(( retval += $? ))
 	fi
 
 	# If setting UTC, don't bother to run hwclock when first booting
@@ -99,7 +99,7 @@ start()
 		else
 			_hwclock --systz $utc_cmd $clock_args
 		fi
-		retval=$(($retval + $?))
+		: $(( retval += $? ))
 	fi
 
 	eend $retval "Failed to set the system clock"
diff --git a/init.d/keymaps.in b/init.d/keymaps.in
index a7bb085e..1b96f493 100644
--- a/init.d/keymaps.in
+++ b/init.d/keymaps.in
@@ -47,7 +47,7 @@ start()
 	n=1
 	while [ $n -le $ttyn ]; do
 		kbd_mode $kmode -C $ttydev$n
-		n=$(($n + 1))
+		: $(( n += 1 ))
 	done
 	eend 0
 
diff --git a/init.d/mixer.in b/init.d/mixer.in
index bb428865..a08aea13 100644
--- a/init.d/mixer.in
+++ b/init.d/mixer.in
@@ -21,7 +21,7 @@ restore()
 			mixer -f "$mixer" \
 			$(cat "/var/db/${mixer#/dev/}-state") >/dev/null
 			veend $?
-			: $((retval += $?))
+			: $(( retval += $? ))
 		fi
 	done
 }
@@ -40,7 +40,7 @@ stop()
 		vebegin "$mixer"
 		mixer -f "$mixer" -s >/var/db/"${mixer#/dev/}"-state
 		veend $?
-		: $((retval += $?))
+		: $(( retval += $? ))
 	done
 	eoutdent
 	eend $retval
diff --git a/init.d/modules.in b/init.d/modules.in
index e6737634..72f14e76 100644
--- a/init.d/modules.in
+++ b/init.d/modules.in
@@ -57,7 +57,7 @@ start()
 		[ -z "$args" ] && eval args=\$module_${aa}_args
 		[ -z "$args" ] && eval args=\$module_${xx}_args
 		eval modprobe -q "$mpargs" "$x" "$args"
-		eend $? "Failed to load $x" && cnt=$(($cnt + 1))
+		eend $? "Failed to load $x" && : $(( cnt += 1 ))
 	done
 	einfo "Autoloaded $cnt module(s)"
 }
diff --git a/init.d/moused.in b/init.d/moused.in
index a41005ff..cdcf36ad 100644
--- a/init.d/moused.in
+++ b/init.d/moused.in
@@ -54,7 +54,7 @@ start()
 		local ttyv=
 		for ttyv in /dev/ttyv*; do
 			vidcontrol < "$ttyv" -m on
-			: $((retval+= $?))
+			: $(( retval += $? ))
 		done
 	fi
 
diff --git a/init.d/net.lo.in b/init.d/net.lo.in
index 66e19456..d647f319 100644
--- a/init.d/net.lo.in
+++ b/init.d/net.lo.in
@@ -115,7 +115,7 @@ _wait_for_carrier()
 			eend 0
 			return 0
 		fi
-		timeout=$((${timeout} - 1))
+		: $(( timeout -= 1 ))
 		[ "${efunc}" = "einfon" ] && printf "."
 	done
 
@@ -144,9 +144,9 @@ _netmask2cidr()
 	local i= len=
 	local IFS=.
 	for i in $1; do
-		while [ ${i} != "0" ]; do
-			len=$((${len} + ${i} % 2))
-			i=$((${i} >> 1))
+		while [ i -ne 0 ]; do
+			: $(( len += i % 2 ))
+			: $(( i >>= 1 ))
 		done
 	done
 
@@ -277,7 +277,7 @@ _gen_module_list()
 		echo "module_${i}_program_start='${PROGRAM_START}'" >> "${MODULESLIST}"
 		echo "module_${i}_program_stop='${PROGRAM_STOP}'" >> "${MODULESLIST}"
 		echo "module_${i}_provide='${PROVIDE}'" >> "${MODULESLIST}"
-		i=$((${i} + 1))
+		: $(( i += 1 ))
 	done
 	echo "module_${i}=" >> "${MODULESLIST}"
 	)
@@ -304,7 +304,7 @@ _load_modules()
 
 	local i=-1 x= mod= f= provides=
 	while true; do
-		i=$((${i} + 1))
+		: $(( i += 1 ))
 		eval mod=\$module_${i}
 		[ -z "${mod}" ] && break
 		[ -e "${MODULESDIR}/${mod}.sh" ] || continue
@@ -438,7 +438,7 @@ _load_config()
 	# so modules can influence it
 	for cmd; do
 		eval config_${config_index}="'${cmd}'"
-		config_index=$((${config_index} + 1))
+		: $(( config_index += 1 ))
 	done
 	# Terminate the list
 	eval config_${config_index}=
@@ -446,7 +446,7 @@ _load_config()
 	config_index=0
 	for cmd in ${fallback}; do
 		eval fallback_${config_index}="'${cmd}'"
-		config_index=$((${config_index} + 1))
+		: $(( config_index += 1 ))
 	done
 	# Terminate the list
 	eval fallback_${config_index}=
@@ -541,7 +541,7 @@ start()
 	if [ -n "${our_metric}" ]; then
 		metric=${our_metric}
 	elif [ "${IFACE}" != "lo" -a "${IFACE}" != "lo0" ]; then
-		metric=$((${metric} + $(_ifindex)))
+		: $(( metric += $(_ifindex) ))
 	fi
 
 	while true; do
@@ -581,11 +581,11 @@ start()
 				eindent
 				eval config_${config_index}=\$config
 				unset fallback_${config_index}
-				config_index=$((${config_index} - 1))
+				: $(( config_index -= 1 ))
 			fi
 		fi
 		eoutdent
-		config_index=$((${config_index} + 1))
+		: $(( config_index += 1 ))
 	done
 
 	if ! ${oneworked}; then
diff --git a/init.d/network.in b/init.d/network.in
index c9341291..1c70785d 100644
--- a/init.d/network.in
+++ b/init.d/network.in
@@ -287,7 +287,7 @@ start()
 		tentative || break
 		[ $r = 5 ] && vebegin "Waiting for tentative addresses"
 		sleep 1
-		r=$(($r - 1))
+		: $(( r -= 1 ))
 	done
 	if [ $r != 5 ]; then
 		[ $r != 0 ]
diff --git a/init.d/numlock.in b/init.d/numlock.in
index c5b894a5..3cb8bee3 100644
--- a/init.d/numlock.in
+++ b/init.d/numlock.in
@@ -21,7 +21,7 @@ _setleds()
 
 	while [ $i -le $ttyn ]; do
 		setleds -D "$1"num < $dev$i || retval=1
-		i=$(($i + 1))
+		: $(( i += 1 ))
 	done
 
 	return $retval
diff --git a/init.d/rc-enabled.in b/init.d/rc-enabled.in
index aff2a406..9ba73b0a 100644
--- a/init.d/rc-enabled.in
+++ b/init.d/rc-enabled.in
@@ -33,7 +33,7 @@ start()
 
 		# Good to go!
 		"$svc" start && started="$started $svc"
-		: $((retval += $?))
+		: $(( retval += $? ))
 	done
 	service_set_value started "$started"
 	eend $retval "Some local rc services failed to start"
@@ -46,7 +46,7 @@ stop()
 	local svc= retval=0
 	for svc in $(rcorder $(service_get_value started) 2>/dev/null | sort -r); do
 		"$svc" stop
-		: $((retval += $?))
+		: $(( retval += $? ))
 	done
 	eend $retval "Some local rc services failed to stop"
 	return 0
diff --git a/init.d/termencoding.in b/init.d/termencoding.in
index 68e49b75..edba715e 100644
--- a/init.d/termencoding.in
+++ b/init.d/termencoding.in
@@ -31,7 +31,7 @@ start()
 	n=1
 	while [ ${n} -le "$ttyn" ]; do
 		printf "\033%s" "$termencoding" >$ttydev$n
-		n=$(($n + 1))
+		: $(( n += 1 ))
 	done
 
 	# Save the encoding for use immediately at boot
diff --git a/init.d/urandom.in b/init.d/urandom.in
index 8233f828..7fe5e590 100644
--- a/init.d/urandom.in
+++ b/init.d/urandom.in
@@ -16,7 +16,7 @@ save_seed()
 	local psz=1
 
 	if [ -e /proc/sys/kernel/random/poolsize ]; then
-		psz=$(($(cat /proc/sys/kernel/random/poolsize) / 4096))
+		: $(( psz = $(cat /proc/sys/kernel/random/poolsize) / 4096 ))
 	fi
 
 	(	# sub shell to prevent umask pollution
diff --git a/man/runscript.8 b/man/runscript.8
index b28bec29..64da26c7 100644
--- a/man/runscript.8
+++ b/man/runscript.8
@@ -449,7 +449,7 @@ eat()
 	veinfo "Eating `basename ${food}`"
 	${command} --eat ${food}
 	retval=$?
-	: $((${result} += ${retval}))
+	: $(( result += retval ))
 	[ ${retval} = 0 ] && ate="${ate} `basename ${food}`"
     done
 
diff --git a/net/apipa.sh b/net/apipa.sh
index 3163104d..ae61233b 100644
--- a/net/apipa.sh
+++ b/net/apipa.sh
@@ -26,20 +26,20 @@ apipa_start()
 	eindent
 
 	while [ ${i} -lt 64516 ]; do
-		i1=$((($(_random) % 255) + 1))
-		i2=$((($(_random) % 255) + 1))
+		: $(( i1 = (_random % 255) + 1 ))
+		: $(( i2 = (_random % 255) + 1 ))
 
 		addr="169.254.${i1}.${i2}"
 		vebegin "${addr}/16"
 		if ! arping_address "${addr}"; then
 			eval config_${config_index}="\"${addr}/16 broadcast 169.254.255.255\""
-			config_index=$((${config_index} - 1))
+			: $(( config_index -= 1 ))
 			veend 0
 			eoutdent
 			return 0
 		fi
 
-		i=$((${i} + 1))
+		: $(( i += 1 ))
 	done
 
 	eerror "No free address found!"
diff --git a/net/arping.sh b/net/arping.sh
index b77d70c1..83360d78 100644
--- a/net/arping.sh
+++ b/net/arping.sh
@@ -34,7 +34,7 @@ arping_address()
 		while [ ${w} -gt 0 -a -z "${foundmac}" ]; do
 			foundmac="$(arping2 ${opts} -r -c 1 -i "${IFACE}" "${ip}" 2>/dev/null | \
 			sed -e 'y/abcdef/ABCDEF/')"
-			w=$((${w} - 1))
+			: $(( w -= 1 ))
 		done
 	else
 		[ -z "$(_get_inet_address)" ] && opts="${opts} -D"
diff --git a/net/clip.sh b/net/clip.sh
index 35efa3f5..2fc290f4 100644
--- a/net/clip.sh
+++ b/net/clip.sh
@@ -148,7 +148,7 @@ clip_post_start()
 
 		local nleftretries=10 emsg= ecode=
 		while [ ${nleftretries} -gt 0 ]; do
-			nleftretries=$((${nleftretries} - 1))
+			: $(( nleftretries -= 1 ))
 	    	emsg="$(atmarp -s "${peerip}" "${ifvpivci}" "$@" 2>&1)"
 	    	ecode=$? && break
 	    	sleep 2
diff --git a/net/ifconfig.sh.BSD.in b/net/ifconfig.sh.BSD.in
index c0c75f08..15c8fb8e 100644
--- a/net/ifconfig.sh.BSD.in
+++ b/net/ifconfig.sh.BSD.in
@@ -38,7 +38,7 @@ _ifindex()
 					echo "${x#/dev/net}"
 					return 0
 				fi
-				i=$((${i} + 1))
+				: $(( i += 1 ))
 			done
 			;;
 		default)
@@ -47,7 +47,7 @@ _ifindex()
 					echo "${i}"
 					return 0
 				fi
-				i=$((${i} + 1))
+				: $(( i += 1 ))
 			done
 			;;
 	esac
diff --git a/net/ifconfig.sh.Linux.in b/net/ifconfig.sh.Linux.in
index a5540c03..dcbd6286 100644
--- a/net/ifconfig.sh.Linux.in
+++ b/net/ifconfig.sh.Linux.in
@@ -26,7 +26,7 @@ _ifindex()
 {
 	local line= i=-2
 	while read line; do
-		i=$((${i} + 1))
+		: $(( i += 1 ))
 		[ ${i} -lt 1 ] && continue
 		case "${line}" in
 			"${IFACE}:"*) echo "${i}"; return 0;;
@@ -34,7 +34,7 @@ _ifindex()
 	done < /proc/net/dev
 
 	# Return the next available index
-	i=$((${i} + 1))
+	: $(( i += 1 ))
 	echo "${i}"
 	return 1
 }
@@ -96,7 +96,7 @@ _get_inet_addresses()
 		_exists || break
 		local addr="$(_get_inet_address)"
 		[ -n "${addr}" ] && addrs="${addrs}${addrs:+ }${addr}"
-		i=$((${i} + 1))
+		: $(( i += 1 ))
 	done
 	echo "${addrs}"
 }
@@ -106,26 +106,26 @@ _cidr2netmask()
 	local cidr="$1" netmask="" done=0 i=0 sum=0 cur=128
 	local octets= frac=
 
-	local octets=$((${cidr} / 8))
-	local frac=$((${cidr} % 8))
+	local octets=$(( cidr / 8 ))
+	local frac=$(( cidr % 8 ))
 	while [ ${octets} -gt 0 ]; do
 		netmask="${netmask}.255"
-		octets=$((${octets} - 1))
-		done=$((${done} + 1))
+		: $(( octets -= 1 ))
+		: $(( done += 1 ))
 	done
 
 	if [ ${done} -lt 4 ]; then
 		while [ ${i} -lt ${frac} ]; do
-			sum=$((${sum} + ${cur}))
-			cur=$((${cur} / 2))
-			i=$((${i} + 1))
+			: $(( sum += cur ))
+			: $(( cur /= 2 ))
+			: $(( i += 1 ))
 		done
 		netmask="${netmask}.${sum}"
-		done=$((${done} + 1))
+		: $(( done += 1 ))
 
 		while [ ${done} -lt 4 ]; do
 			netmask="${netmask}.0"
-			done=$((${done} + 1))
+			: $(( done += 1 ))
 		done
 	fi
 
@@ -150,7 +150,7 @@ _add_address()
 		# Get the last alias made for the interface and add 1 to it
 		i=$(ifconfig | sed '1!G;h;$!d' | grep -m 1 -o "^${iface}:[0-9]*" \
 			| sed -n -e 's/'"${iface}"'://p')
-		i=$((${i:-0} + 1))
+		: $(( i = ${i:-0} + 1 ))
 		iface="${iface}:${i}"
 	fi
 
diff --git a/net/ifplugd.sh b/net/ifplugd.sh
index d048b61a..0bcde2f3 100644
--- a/net/ifplugd.sh
+++ b/net/ifplugd.sh
@@ -72,7 +72,7 @@ ifplugd_pre_start()
 		fi
 		sleep 1
 		[ ${timeout} -eq 0 ] && continue
-		i=$((${i} + 1))
+		: $(( i += 1 ))
 		[ ${i} -ge ${timeout} ] && break
 	done
 
diff --git a/net/ip6to4.sh b/net/ip6to4.sh
index 0e94293f..45644507 100644
--- a/net/ip6to4.sh
+++ b/net/ip6to4.sh
@@ -51,7 +51,7 @@ ip6to4_start()
 					case "${ip}" in
 						172.${i}.*) break;;
 					esac
-					i=$((${i} + 1))
+					: $(( i += 1 ))
 				done
 				[ ${i} -lt 32 ] && continue
 				;;
@@ -90,7 +90,7 @@ ip6to4_start()
 
 	# Now apply our config
 	eval config_${config_index}=\'"${new}"\'
-	config_index=$((${config_index} - 1))
+	: $(( config_index -= 1 ))
 
 	# Add a route for us, ensuring we don't delete anything else
 	local routes="$(_get_array "routes_${IFVAR}")
diff --git a/net/iproute2.sh b/net/iproute2.sh
index 660d5147..91282ea6 100644
--- a/net/iproute2.sh
+++ b/net/iproute2.sh
@@ -36,7 +36,7 @@ _ifindex()
 {
 	local line= i=-2
 	while read line; do
-		i=$((${i} + 1))
+		: $(( i += 1 ))
 		[ ${i} -lt 1 ] && continue
 		case "${line}" in
 			"${IFACE}:"*) echo "${i}"; return 0;;
@@ -44,7 +44,7 @@ _ifindex()
 	done < /proc/net/dev
 
 	# Return the next available index
-	i=$((${i} + 1))
+	: $(( i += 1 ))
 	echo "${i}"
 	return 1
 }
@@ -290,7 +290,7 @@ iproute2_post_start()
 		while [ $n -ge 0 ]; do
 			_iproute2_ipv6_tentative || break
 			sleep 1
-			n=$(($n - 1))
+			: $(( n -= 1 ))
 		done
 		[ $n -ge 0 ]
 		eend $?
diff --git a/net/iwconfig.sh.BSD.in b/net/iwconfig.sh.BSD.in
index 850d70b2..3acaf663 100644
--- a/net/iwconfig.sh.BSD.in
+++ b/net/iwconfig.sh.BSD.in
@@ -218,7 +218,7 @@ iwconfig_associate()
 		sleep 1
 
 		[ ${timeout} -eq 0 ] && continue
-		i=$((${i} +  1))
+		: $(( i +=  1 ))
 		[ ${i} -ge ${timeout} ] && { eend 1; return 1; }
 	done
 
@@ -252,13 +252,13 @@ iwconfig_scan()
 	scan="$(LC_ALL=C ifconfig -v "${IFACE}" list scan 2>/dev/null | sed -e "1 d" -e "s/$/'/g" -e "s/^/'/g")"
 	while [ ${i} -lt 3 -a -z "${scan}" ] ; do
 		scan="${scan}${scan:+ }$(LC_ALL=C ifconfig -v "${IFACE}" scan 2>/dev/null | sed -e "1 d" -e "s/$/'/g" -e "s/^/'/g")"
-		i=$((${i} + 1))
+		: $(( i += 1 ))
 	done
 
 	APS=-1
 	eval set -- ${scan}
 	for line in "$@" ; do
-		APS=$((${APS} + 1))
+		: $(( APS += 1 ))
 		set -- ${line}
 		while true ; do
 			case "$1" in
@@ -276,7 +276,7 @@ iwconfig_scan()
 		# Add 1000 for managed nodes as we prefer them to adhoc
 		set -- $*
 		case "$1" in
-			*E*) eval QUAL_${APS}=$((${quality} + 1000)) ;;
+			*E*) eval QUAL_${APS}=$(( quality + 1000 )) ;;
 			*)   eval QUAL_${APS}=\$quality ;;
 		esac
 	done
@@ -290,7 +290,7 @@ iwconfig_scan()
 	# Sort based on quality
 	local i=0 k=1 a= b= x= t=
 	while [ ${i} -lt ${APS} ] ; do
-		k=$((${i} + 1))
+		: $(( k = i + 1 ))
 		while [ ${k} -le ${APS} ] ; do
 			eval a=\$QUALITY_${i}
 			[ -z "${a}" ] && break
@@ -302,15 +302,15 @@ iwconfig_scan()
 					eval ${x}_${k}=\$t
 				done
 			fi
-			k=$((${k} + 1))
+			: $(( k += 1 ))
 		done
-		i=$((${i} + 1))
+		: $(( i += 1 ))
 	done
 
 	# Strip any duplicates
 	local i=0 k=1 a= b=
 	while [ ${i} -lt ${APS} ] ; do
-		k=$((${i} + 1))
+		: $(( k = i + 1 ))
 		while [ ${k} -le ${APS} ] ; do
 			eval a=\$MAC_${i}
 			eval b=\$MAC_${k}
@@ -327,9 +327,9 @@ iwconfig_scan()
 					unset MAC_${k} SSID_${k} CHAN_${k} QUALITY_${k} CAPS_${k}
 				fi
 			fi
-			k=$((${k} + 1))
+			: $(( k += 1 ))
 		done
-		i=$((${i} + 1))
+		: $(( i += 1 ))
 	done
 
 	local i=0 e= m= s=
@@ -337,7 +337,7 @@ iwconfig_scan()
 	while [ ${i} -le ${APS} ] ; do
 		eval x=\$MAC_${i}
 		if [ -z "${x}" ] ; then
-			i=$((${i} + 1))
+			: $(( i += 1 ))
 			continue
 		fi
 
@@ -374,7 +374,7 @@ iwconfig_scan()
 				unset SSID_${i} MAC_${i} CHAN_${i} QUALITY_${i} CAPS_${i}
 			fi
 		done
-		i=$((${i} + 1))
+		: $(( i += 1 ))
 	done
 	eoutdent
 	return 0
@@ -396,7 +396,7 @@ iwconfig_force_preferred()
 				found_AP=true
 				break
 			fi
-			i=$((${i} + 1))
+			: $(( i += 1 ))
 		done
 		if ! ${found_AP} ; then
 			SSID=${ssid}
@@ -428,7 +428,7 @@ iwconfig_connect_preferred()
 				iwconfig_associate "${mac}" \
 				"${chan}" "${caps}" && return 0
 			fi
-			i=$((${i} + 1))
+			: $(( i += 1 ))
 		done
 	done
 
@@ -442,7 +442,7 @@ iwconfig_connect_not_preferred()
 	while [ ${i} -le ${APS} ] ; do
 		eval e=\$SSID_${i}
 		if [ -z "${e}" ] ; then
-			i=$((${i} + 1))
+			: $(( i += 1 ))
 			continue
 		fi
 
@@ -465,7 +465,7 @@ iwconfig_connect_not_preferred()
 			iwconfig_associate "${mac}"  \
 			"${chan}" "${caps}" && return 0
 		fi
-		i=$((${i} + 1))
+		: $(( i += 1 ))
 	done
 
 	return 1
diff --git a/net/iwconfig.sh.Linux.in b/net/iwconfig.sh.Linux.in
index 199678f5..293bc1f3 100644
--- a/net/iwconfig.sh.Linux.in
+++ b/net/iwconfig.sh.Linux.in
@@ -39,7 +39,7 @@ _get_ssid()
 			return 0
 		fi
 		sleep 1
-		i=$((${i} - 1))
+		: $(( i -= 1 ))
 	done
 
 	return 1
@@ -229,7 +229,7 @@ iwconfig_wait_for_association()
 
 		sleep 1
 		[ ${timeout} -eq 0 ] && continue
-		i=$((${i} +  1))
+		: $(( i +=  1 ))
 		[ ${i} -ge ${timeout} ] && return 1
 	done
 	return 1
@@ -347,7 +347,7 @@ iwconfig_scan()
 					;;
 			esac
 		fi
-	    i=$((${i} + 1))
+	    : $(( i += 1 ))
 	done
 
 	if [ -z "${scan}" ]; then
@@ -377,7 +377,7 @@ iwconfig_scan()
 	for line; do
 		case "${line}" in
 			*Address:*)
-				APS=$((${APS} + 1))
+				: $(( APS += 1 ))
 				eval MAC_${APS}="\""$(echo "${line#*: }" | tr '[:lower:]' '[:upper:]')"\""
 				eval QUALITY_${APS}=0
 				;;
@@ -427,7 +427,7 @@ iwconfig_scan()
 	# Sort based on quality
 	local i=0 k=1 a= b= x= t=
 	while [ ${i} -lt ${APS} ]; do
-	    k=$((${i} + 1))
+	    : $(( k = i + 1 ))
 	    while [ ${k} -le ${APS} ]; do
 		eval a=\$QUALITY_${i}
 		[ -z "${a}" ] && break
@@ -439,15 +439,15 @@ iwconfig_scan()
 			eval ${x}_${k}=\$t
 		    done
 		fi
-		k=$((${k} + 1))
+		: $(( k += 1 ))
 	    done
-	    i=$((${i} + 1))
+	    : $(( i += 1 ))
 	done
 
 	# Strip any duplicates
 	local i=0 k=1 a= b=
 	while [ ${i} -lt ${APS} ]; do
-		k=$((${i} + 1))
+		: $(( k = i + 1 ))
 		while [ ${k} -le ${APS} ]; do
 			eval a=\$MAC_${i}
 			eval b=\$MAC_${k}
@@ -459,9 +459,9 @@ iwconfig_scan()
 				[ -n "${a}" -a -n "${b}" ] && [ "${a}" -lt "${b}" ] && u=${i}
 				unset MAC_${u} SSID_${u} MODE_${u} CHAN_${u} QUALITY_${u} ENC_${u}
 			fi
-			k=$((${k} + 1))
+			: $(( k += 1 ))
 		done
-		i=$((${i} + 1))
+		: $(( i += 1 ))
 	done
 
 	local i=0 e= m= s=
@@ -469,7 +469,7 @@ iwconfig_scan()
 	while [ ${i} -le ${APS} ]; do
 		eval x=\$MAC_${i}
 		if [ -z "${x}" ]; then
-		    i=$((${i} + 1))
+		    : $(( i += 1 ))
 		    continue
 		fi
 
@@ -506,7 +506,7 @@ iwconfig_scan()
 				unset SSID_${i} MAC_${i} ${MODE}_${i} CHAN_${i} QUALITY_${i} ENC_${i}
 			fi
 		done
-		i=$((${i} + 1))
+		: $(( i += 1 ))
 	done
 	eoutdent
 }
@@ -526,7 +526,7 @@ iwconfig_force_preferred()
 				found_AP=true
 				break
 			fi
-			i=$((${i} + 1))
+			: $(( i += 1 ))
 		done
 		if ! ${found_AP}; then
 			SSID=${ssid}
@@ -559,7 +559,7 @@ iwconfig_connect_preferred()
 				iwconfig_associate "${mode}" "${mac}" "${enc}" "${freq}" \
 					"${chan}" && return 0
 			fi
-			i=$((${i} + 1))
+			: $(( i += 1 ))
 		done
 	done
 
@@ -593,7 +593,7 @@ iwconfig_connect_not_preferred()
 					"${chan}" && return 0
 			fi
 		fi
-		i=$((${i} + 1))
+		: $(( i += 1 ))
 	done
 
 	return 1
diff --git a/net/netplugd.sh b/net/netplugd.sh
index f7df7a39..f43a5e64 100644
--- a/net/netplugd.sh
+++ b/net/netplugd.sh
@@ -74,7 +74,7 @@ netplugd_pre_start()
 		fi
 		sleep 1
 		[ ${timeout} -eq 0 ] && continue
-		i=$((${i} + 1))
+		: $(( i += 1 ))
 		[ ${i} -ge ${timeout} ] && break
 	done
 
diff --git a/net/pppd.sh b/net/pppd.sh
index 1f9d302e..97bd3ee5 100644
--- a/net/pppd.sh
+++ b/net/pppd.sh
@@ -96,7 +96,7 @@ pppd_pre_start()
 	if ! ${hasdefaultmetric}; then
 		local m=
 		eval m=\$metric_${IFVAR}
-		[ -z "${m}" ] && m=$((${metric} + $(_ifindex)))
+		[ -z "${m}" ] && : $(( m = metric + $(_ifindex) ))
 		opts="${opts} defaultmetric ${m}"
 	fi
 	if [ -n "${mtu}" ]; then
diff --git a/net/tuntap.sh b/net/tuntap.sh
index 884e0ab7..ac505abb 100644
--- a/net/tuntap.sh
+++ b/net/tuntap.sh
@@ -30,7 +30,7 @@ tuntap_pre_start()
 		local timeout=10
 		while [ ! -e /dev/net/tun -a ${timeout} -gt 0 ]; do
 			sleep 1
-			timeout=$((${timeout} - 1))
+			: $(( timeout -= 1 ))
 		done
 		if [ ! -e /dev/net/tun ]; then
 			eerror "TUN/TAP support present but /dev/net/tun is not"
diff --git a/net/wpa_supplicant.sh b/net/wpa_supplicant.sh
index 91de49ef..53b0256c 100644
--- a/net/wpa_supplicant.sh
+++ b/net/wpa_supplicant.sh
@@ -34,7 +34,7 @@ _get_ssid()
 			return 0
 		fi
 		sleep 1
-		timeout=$((timeout - 1))
+		: $(( timeout -= 1 ))
 	done
 
 	return 1
diff --git a/sh/functions.sh.in b/sh/functions.sh.in
index 1d1b0cd0..b00ec68e 100644
--- a/sh/functions.sh.in
+++ b/sh/functions.sh.in
@@ -8,14 +8,14 @@ RC_GOT_FUNCTIONS="yes"
 
 eindent()
 {
-	EINFO_INDENT=$((${EINFO_INDENT:-0} + 2))
+	: $(( EINFO_INDENT = ${EINFO_INDENT:-0} + 2 ))
 	[ "$EINFO_INDENT" -gt 40 ] && EINFO_INDENT=40
 	export EINFO_INDENT
 }
 
 eoutdent()
 {
-	EINFO_INDENT=$((${EINFO_INDENT:-0} - 2))
+	: $(( EINFO_INDENT = ${EINFO_INDENT:-0} - 2 ))
 	[ "$EINFO_INDENT" -lt 0 ] && EINFO_INDENT=0
 	return 0
 }
diff --git a/sh/rc-mount.sh b/sh/rc-mount.sh
index b3c9bf63..2bb14504 100644
--- a/sh/rc-mount.sh
+++ b/sh/rc-mount.sh
@@ -59,7 +59,7 @@ do_unmount()
 						eend 1
 					else
 						local sig="TERM"
-						retry=$(($retry - 1))
+						: $(( retry -= 1 ))
 						[ $retry = 1 ] && sig="KILL"
 						fuser $f_kill$sig -k $f_opts \
 							"$mnt" >/dev/null 2>&1
diff --git a/sh/runtests.sh b/sh/runtests.sh
index 7f7e7bdd..f083ff46 100755
--- a/sh/runtests.sh
+++ b/sh/runtests.sh
@@ -9,17 +9,17 @@ tret=0
 ebegin "Testing yesno()"
 for f in yes YES Yes true TRUE True 1 ; do
 	if ! yesno $f; then
-		tret=$(($tret + 1))
+		: $(( tret += 1 ))
 		echo "!$f!"
 	fi
 done
 for f in no NO No false FALSE False 0 ; do
 	if yesno $f; then
-		tret=$(($tret + 1))
+		: $(( tret += 1 ))
 		echo "!$f!"
 	fi
 done
 eend $tret
-ret=$(($ret + $tret))
+: $(( ret += $tret ))
 
 exit $ret
diff --git a/src/test/runtests.sh b/src/test/runtests.sh
index 4731bd7e..a4b3f189 100755
--- a/src/test/runtests.sh
+++ b/src/test/runtests.sh
@@ -15,7 +15,7 @@ checkit() {
 	echo "$@" | tr ' ' '\n' > ${base}.out
 	diff -u ${base}.list ${base}.out
 	eend $?
-	ret=$(($ret + $?))
+	: $(( ret += $? ))
 }
 
 ret=0
@@ -65,7 +65,7 @@ readelf -Wr $(grep -l '#include[[:space:]]"librc\.h"' ${librc_srcdir}/*.c | sed
 syms=$(diff -u librc.funcs.hidden.list librc.funcs.hidden.out | sed -n '/^+[^+]/s:^+::p')
 [ -z "${syms}" ]
 eend $? "Missing hidden defs:"$'\n'"${syms}"
-ret=$(($ret + $?))
+: $(( ret += $? ))
 
 ebegin "Checking trailing whitespace in code"
 # XXX: Should we check man pages too ?
@@ -118,7 +118,7 @@ for u in units/*; do
 	ebegin "$(basename "${u}")"
 	./"${u}"
 	eend $?
-	ret=$(($ret + $?))
+	: $(( ret += $? ))
 done
 
 exit ${ret}
diff --git a/support/openvpn/up.sh b/support/openvpn/up.sh
index 14569325..c52ea048 100755
--- a/support/openvpn/up.sh
+++ b/support/openvpn/up.sh
@@ -34,7 +34,7 @@ while true; do
 	elif [ "${opt}" != "${opt#dhcp-option DNS *}" ]; then
 		NS="${NS}nameserver ${opt#dhcp-option DNS *}\n"
 	fi
-	i=$((${i} + 1))
+	: $(( i += 1 ))
 done
 
 if [ -n "${NS}" ]; then