diff --git a/boards/airfy-beacon/Makefile.include b/boards/airfy-beacon/Makefile.include
index cc8572b7ccbb09ae657335cf6af1a6cbc53213dc..14eaf500140682e889ceb5a65231a07a2f0846ee 100644
--- a/boards/airfy-beacon/Makefile.include
+++ b/boards/airfy-beacon/Makefile.include
@@ -4,7 +4,7 @@ export CPU_MODEL = nrf51x22xxaa
 
 # define the default port depending on the host OS
 PORT_LINUX ?= /dev/ttyUSB0
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.SLAB_USBtoUART* | head -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.SLAB_USBtoUART*)))
 
 # setup serial terminal
 include $(RIOTBOARD)/Makefile.include.serial
diff --git a/boards/arduino-due/Makefile.include b/boards/arduino-due/Makefile.include
index 10b858a74b163a6482570dc2a15ea5893e110c62..08c0eefea7ca3f1137ade50161c70ede07a01fcb 100644
--- a/boards/arduino-due/Makefile.include
+++ b/boards/arduino-due/Makefile.include
@@ -4,7 +4,7 @@ export CPU_MODEL = sam3x8e
 
 # define the default port depending on the host OS
 PORT_LINUX ?= /dev/ttyACM0
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.usbmodem* | head -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.usbmodem*)))
 
 # define board specific flasher options
 export FLASHER = $(RIOTBOARD)/$(BOARD)/dist/flash.sh
diff --git a/boards/ek-lm4f120xl/Makefile.include b/boards/ek-lm4f120xl/Makefile.include
index 94d73953881f21bdc2f9e5cc10729d3b9db61fac..373406db2e4a5bd04d8b6741d94a74428f0c4aa7 100644
--- a/boards/ek-lm4f120xl/Makefile.include
+++ b/boards/ek-lm4f120xl/Makefile.include
@@ -4,7 +4,7 @@ export CPU_MODEL = LM4F120H5QR
 
 #define the default port depending on the host OS
 PORT_LINUX ?= /dev/ttyACM0
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.usbmodem* | head -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.usbmodem*)))
 
 # setup serial terminal
 include $(RIOTBOARD)/Makefile.include.serial
diff --git a/boards/f4vi1/Makefile.include b/boards/f4vi1/Makefile.include
index 1d9b4b020060194cba8f96af1f8e182d9afcdc74..19d12fd50ec9a268e25699846d6dac8cecd53d02 100644
--- a/boards/f4vi1/Makefile.include
+++ b/boards/f4vi1/Makefile.include
@@ -4,7 +4,7 @@ export CPU_MODEL = stm32f415rg
 
 # define the default port depending on the host OS
 PORT_LINUX ?= /dev/ttyUSB0
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.SLAB_USBtoUART* | head -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.SLAB_USBtoUART*)))
 
 # setup serial terminal
 include $(RIOTBOARD)/Makefile.include.serial
diff --git a/boards/fox/Makefile.include b/boards/fox/Makefile.include
index fe9d27d1083dedcc4087e06caa88a16e7f8387f5..cd16e056dcbff2343921322a6020ccfb7f6b2d3c 100644
--- a/boards/fox/Makefile.include
+++ b/boards/fox/Makefile.include
@@ -4,7 +4,7 @@ export CPU_MODEL = stm32f103re
 
 # set default port depending on operating system
 PORT_LINUX ?= /dev/ttyUSB1
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.usbserial* | head -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.usbserial*)))
 
 # setup serial terminal
 include $(RIOTBOARD)/Makefile.include.serial
diff --git a/boards/iotlab-m3/Makefile.include b/boards/iotlab-m3/Makefile.include
index f291c025ca0e853af3ef637d74ff16cc8ac35877..b0a76057cb960bee5b0f750caffe8206b7dcfd58 100644
--- a/boards/iotlab-m3/Makefile.include
+++ b/boards/iotlab-m3/Makefile.include
@@ -4,7 +4,7 @@ export CPU_MODEL = stm32f103re
 
 # define the default port depending on the host OS
 PORT_LINUX ?= /dev/ttyUSB1
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.usbserial* | head -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.usbserial*)))
 
 # setup serial terminal
 export BAUD = 500000
diff --git a/boards/limifrog-v1/Makefile.include b/boards/limifrog-v1/Makefile.include
index e40282f74acb1afc6c000cec4d3e27604c7ca50f..40636539362b8fa8a9b5cf5be938807dd9ec93e2 100644
--- a/boards/limifrog-v1/Makefile.include
+++ b/boards/limifrog-v1/Makefile.include
@@ -4,7 +4,7 @@ export CPU_MODEL = stm32l151rc
 
 # define the default port depending on the host OS
 PORT_LINUX ?= /dev/ttyUSB0
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.SLAB_USBtoUART* | head -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.SLAB_USBtoUART*)))
 
 # setup serial terminal
 include $(RIOTBOARD)/Makefile.include.serial
diff --git a/boards/mbed_lpc1768/Makefile.include b/boards/mbed_lpc1768/Makefile.include
index 630e0528f227a81ae6c22a8421eeea512341f153..e6c64263cb4c7c03f427eedfa3236c533e79b97f 100644
--- a/boards/mbed_lpc1768/Makefile.include
+++ b/boards/mbed_lpc1768/Makefile.include
@@ -12,7 +12,7 @@ export DEBUGGER_FLAGS =
 
 # define the default port depending on the host OS
 PORT_LINUX ?= /dev/ttyACM0
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.SLAB_USBtoUART* | head -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.SLAB_USBtoUART*)))
 
 # setup serial terminal
 include $(RIOTBOARD)/Makefile.include.serial
diff --git a/boards/msb-430-common/Makefile.include b/boards/msb-430-common/Makefile.include
index af7e9f442cfa4084372bfb8b9243ebb06213140e..71bc5200b909b683df530cff8eab1c93723cde6a 100644
--- a/boards/msb-430-common/Makefile.include
+++ b/boards/msb-430-common/Makefile.include
@@ -4,7 +4,7 @@ export CPU_MODEL = msp430f1612
 
 # set default port depending on operating system
 PORT_LINUX ?= /dev/ttyUSB0
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.SLAB_USBtoUART* | head -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.SLAB_USBtoUART*)))
 # setup serial terminal
 include $(RIOTBOARD)/Makefile.include.serial
 
diff --git a/boards/msbiot/Makefile.include b/boards/msbiot/Makefile.include
index 2f8ee328ffa1e0ff008beaed11eb79e9ad5d253f..1df898f14cf5db6e207ccbb5019998b986fe2768 100644
--- a/boards/msbiot/Makefile.include
+++ b/boards/msbiot/Makefile.include
@@ -4,7 +4,7 @@ export CPU_MODEL = stm32f415rg
 
 #define the default port depending on the host OS
 PORT_LINUX ?= /dev/ttyUSB0
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.SLAB_USBtoUART* | head -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.SLAB_USBtoUART*)))
 
 # setup serial terminal
 include $(RIOTBOARD)/Makefile.include.serial
diff --git a/boards/mulle/Makefile.include b/boards/mulle/Makefile.include
index 2ed218e7d798cc4fa6926a45bcecc1fb80ce4d0e..49392d7ceec17dd9da4da31ea187fffab88fde78 100644
--- a/boards/mulle/Makefile.include
+++ b/boards/mulle/Makefile.include
@@ -82,7 +82,7 @@ ifeq ($(PORT),)
       PORT := $(shell $(RIOTBASE)/dist/tools/usb-serial/find-tty.sh)
   endif
   else ifeq ($(OS),Darwin)
-    PORT := $(shell ls -1 /dev/tty.usbserial* | head -n 1)
+    PORT := $(firstword $(sort $(wildcard /dev/tty.usbserial*)))
   endif
 endif
 ifeq ($(PORT),)
diff --git a/boards/nrf51dongle/Makefile.include b/boards/nrf51dongle/Makefile.include
index 76f48a1f71de3b064eeda18a6209825feda2e024..53810879fd45ebb1429e96c04b4fb7fcec7ed1fb 100644
--- a/boards/nrf51dongle/Makefile.include
+++ b/boards/nrf51dongle/Makefile.include
@@ -4,7 +4,7 @@ export CPU_MODEL = nrf51x22xxab
 
 # define the default port depending on the host OS
 PORT_LINUX ?= /dev/ttyACM0
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.SLAB_USBtoUART* | head -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.SLAB_USBtoUART*)))
 
 # setup JLink for flashing
 export JLINK_DEVICE := nrf51822
diff --git a/boards/nrf52dk/Makefile.include b/boards/nrf52dk/Makefile.include
index e6a37d3ae95efc2030b8572732da5cb086961248..e16b064a4d57b818b7b5138071b2070e1985c842 100644
--- a/boards/nrf52dk/Makefile.include
+++ b/boards/nrf52dk/Makefile.include
@@ -4,7 +4,7 @@ export CPU_MODEL = nrf52xxaa
 
 # set default port depending on operating system
 PORT_LINUX ?= /dev/ttyACM0
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.usbmodem* | head -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.usbmodem*)))
 
 # setup the boards dependencies
 include $(RIOTBOARD)/$(BOARD)/Makefile.dep
diff --git a/boards/nrf6310/Makefile.include b/boards/nrf6310/Makefile.include
index 6fcf0d217d2618db2d1feb155898ec3279da263a..6db9e3a7bd61063aa3992931b10983ada8653d6d 100644
--- a/boards/nrf6310/Makefile.include
+++ b/boards/nrf6310/Makefile.include
@@ -4,7 +4,7 @@ export CPU_MODEL = nrf51x22xxaa
 
 # set default port depending on operating system
 PORT_LINUX ?= /dev/ttyUSB0
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.SLAB_USBtoUART* | head -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.SLAB_USBtoUART*)))
 
 # define flash and debugging environment
 export FLASHER = $(RIOTBOARD)/$(BOARD)/dist/flash.sh
diff --git a/boards/nucleo-f091/Makefile.include b/boards/nucleo-f091/Makefile.include
index 97b59fc9e07b6ec7c53b4c24a3d7dcfb3251b6ed..55cf92fcc0ad0e751d62ccce24e7f791cbc5a755 100644
--- a/boards/nucleo-f091/Makefile.include
+++ b/boards/nucleo-f091/Makefile.include
@@ -4,7 +4,7 @@ export CPU_MODEL = stm32f091rc
 
 #define the default port depending on the host OS
 PORT_LINUX ?= /dev/ttyACM0
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.usbmodem* | head -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.usbmodem*)))
 
 # setup serial terminal
 include $(RIOTBOARD)/Makefile.include.serial
diff --git a/boards/nucleo-f103/Makefile.include b/boards/nucleo-f103/Makefile.include
index a23e997856912c0cb4ef89d22d71aaf3cfd3d7bd..f1b362445f250eb96299442891304e092b0eb2a1 100755
--- a/boards/nucleo-f103/Makefile.include
+++ b/boards/nucleo-f103/Makefile.include
@@ -4,7 +4,7 @@ export CPU_MODEL = stm32f103rb
 
 #define the default port depending on the host OS
 PORT_LINUX ?= /dev/ttyUSB0
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.usbmodem* | head -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.usbmodem*)))
 
 # setup serial terminal
 include $(RIOTBOARD)/Makefile.include.serial
diff --git a/boards/nucleo-f303/Makefile.include b/boards/nucleo-f303/Makefile.include
index b65ef8a2c5c003faf1ffa9b414b4bb2b8a4a1b5c..aca137caf3992bf2390481b3e0e93d494621b455 100755
--- a/boards/nucleo-f303/Makefile.include
+++ b/boards/nucleo-f303/Makefile.include
@@ -4,7 +4,7 @@ export CPU_MODEL = stm32f303re
 
 #define the default port depending on the host OS
 PORT_LINUX ?= /dev/ttyUSB0
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.usbmodem* | head -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.usbmodem*)))
 
 # setup serial terminal
 include $(RIOTBOARD)/Makefile.include.serial
diff --git a/boards/nucleo-f334/Makefile.include b/boards/nucleo-f334/Makefile.include
index b3d8ea9bea2ac043eb5572dbb347fced5c2d3861..edf7af40360a4aae51c5f0c84c04d278c7dd0cc5 100644
--- a/boards/nucleo-f334/Makefile.include
+++ b/boards/nucleo-f334/Makefile.include
@@ -4,7 +4,7 @@ export CPU_MODEL = stm32f334r8
 
 #define the default port depending on the host OS
 PORT_LINUX ?= /dev/ttyACM0
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.usbmodem* | head -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.usbmodem*)))
 
 # setup serial terminal
 include $(RIOTBOARD)/Makefile.include.serial
diff --git a/boards/nucleo-f401/Makefile.include b/boards/nucleo-f401/Makefile.include
index 5d99f17c20f458b65b0f2d461b6236450ee6be14..d2ca4cad2138180194857003d270c279f09e15fc 100644
--- a/boards/nucleo-f401/Makefile.include
+++ b/boards/nucleo-f401/Makefile.include
@@ -4,7 +4,7 @@ export CPU_MODEL = stm32f401re
 
 # define the default port depending on the host OS
 PORT_LINUX ?= /dev/ttyACM0
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.usbmodem* | head -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.usbmodem*)))
 
 # setup serial terminal
 include $(RIOTBOARD)/Makefile.include.serial
diff --git a/boards/nucleo-l1/Makefile.include b/boards/nucleo-l1/Makefile.include
index dd05d8f352b9b141bba9cf5ca0160c5216a7fd55..4a9e698d24fb363e96addd59109dc19fe2b0b367 100644
--- a/boards/nucleo-l1/Makefile.include
+++ b/boards/nucleo-l1/Makefile.include
@@ -4,7 +4,7 @@ export CPU_MODEL = stm32l152ret6
 
 # define the default port depending on the host OS
 PORT_LINUX ?= /dev/ttyACM0
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.SLAB_USBtoUART* | head -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.SLAB_USBtoUART*)))
 
 # setup serial terminal
 include $(RIOTBOARD)/Makefile.include.serial
diff --git a/boards/openmote-cc2538/Makefile.include b/boards/openmote-cc2538/Makefile.include
index 603c277d3f6b1d1659bea7f4830f8188a51a22fb..1681566a1d3023c4690af2a03db25fa8bae599b6 100644
--- a/boards/openmote-cc2538/Makefile.include
+++ b/boards/openmote-cc2538/Makefile.include
@@ -4,7 +4,7 @@ export CPU_MODEL = cc2538sf53
 
 # define the default port depending on the host OS
 PORT_LINUX ?= /dev/ttyUSB0
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.usbserial-* | head -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.usbserial*)))
 
 # setup JLink for flashing
 export JLINK_DEVICE := cc2538sf53
diff --git a/boards/pca10000/Makefile.include b/boards/pca10000/Makefile.include
index a2fb34f60f5a4c427442e306dd5a9fa7fb778e4c..7b11716814e57b2fb9d4f5b7d5edb146353dffa4 100644
--- a/boards/pca10000/Makefile.include
+++ b/boards/pca10000/Makefile.include
@@ -4,7 +4,7 @@ export CPU_MODEL = nrf51x22xxaa
 
 # define the default port depending on the host OS
 PORT_LINUX ?= /dev/ttyACM0
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.SLAB_USBtoUART* | head -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.SLAB_USBtoUART*)))
 
 # setup JLink for flashing
 export JLINK_DEVICE := nrf51822
diff --git a/boards/pca10005/Makefile.include b/boards/pca10005/Makefile.include
index ee3ebaa2355fdcaafec9fa2fe9995db11fe97f03..202562d2d31690f98e42c69ef2ae51aee04af5a9 100644
--- a/boards/pca10005/Makefile.include
+++ b/boards/pca10005/Makefile.include
@@ -4,7 +4,7 @@ export CPU_MODEL = nrf51x22xxaa
 
 # set default port depending on operating system
 PORT_LINUX ?= /dev/ttyUSB0
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.SLAB_USBtoUART* | head -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.SLAB_USBtoUART*)))
 
 # setup JLink for flashing
 export JLINK_DEVICE := nrf51822
diff --git a/boards/remote/Makefile.include b/boards/remote/Makefile.include
index 7eb3015c0ecf30899130bdf836c9865f03df1294..452a14daed09349c5e3972c24170a5220f75ab08 100644
--- a/boards/remote/Makefile.include
+++ b/boards/remote/Makefile.include
@@ -4,7 +4,7 @@ export CPU_MODEL = cc2538sf53
 
 # define the default port depending on the host OS
 PORT_LINUX  ?= /dev/ttyUSB1
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.usbserial-* | head -n 2 | tail -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.usbserial*)))
 
 # define the default flash-tool
 export PROGRAMMER ?= cc2538-bsl
diff --git a/boards/samr21-xpro/Makefile.include b/boards/samr21-xpro/Makefile.include
index f16f5d8744aeac5f34ed4468eb8c895d0bba621d..851983a6665587e514a4748ef466fc0dfc834a55 100644
--- a/boards/samr21-xpro/Makefile.include
+++ b/boards/samr21-xpro/Makefile.include
@@ -4,7 +4,7 @@ export CPU_MODEL = samr21g18a
 
 # set default port depending on operating system
 PORT_LINUX ?= /dev/ttyACM0
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.usbmodem* | head -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.usbmodem*)))
 
 # setup the boards dependencies
 include $(RIOTBOARD)/$(BOARD)/Makefile.dep
diff --git a/boards/slwstk6220a/Makefile.include b/boards/slwstk6220a/Makefile.include
index 59057d72b3a81f8922b5b7d1fd5cb606221d678d..3e6a7aac0ef0f7c6b8ff5ac6efea0dd3c7a694b0 100644
--- a/boards/slwstk6220a/Makefile.include
+++ b/boards/slwstk6220a/Makefile.include
@@ -4,7 +4,7 @@ export CPU_MODEL = ezr32wg330f256r60
 
 # set default port depending on operating system
 PORT_LINUX ?= /dev/ttyACM0
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.usbmodem* | head -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.usbmodem*)))
 
 # setup the boards dependencies
 include $(RIOTBOARD)/$(BOARD)/Makefile.dep
diff --git a/boards/stm32f0discovery/Makefile.include b/boards/stm32f0discovery/Makefile.include
index 9bce9d87bbe8a70a7dc6d94ad5ccef28ee1a5a75..f0a04d1444c6bebedfc5af05fe295c090d89ab83 100644
--- a/boards/stm32f0discovery/Makefile.include
+++ b/boards/stm32f0discovery/Makefile.include
@@ -4,7 +4,7 @@ export CPU_MODEL = stm32f051r8
 
 # define the default port depending on the host OS
 PORT_LINUX ?= /dev/ttyUSB0
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.SLAB_USBtoUART* | head -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.SLAB_USBtoUART*)))
 
 # setup serial terminal
 include $(RIOTBOARD)/Makefile.include.serial
diff --git a/boards/stm32f3discovery/Makefile.include b/boards/stm32f3discovery/Makefile.include
index fa0286a2569c3cf899949372c250c797c2e9fe52..4389d6e7d91828eb303c70c53e993d375320a671 100644
--- a/boards/stm32f3discovery/Makefile.include
+++ b/boards/stm32f3discovery/Makefile.include
@@ -4,7 +4,7 @@ export CPU_MODEL = stm32f303vc
 
 # define the default port depending on the host OS
 PORT_LINUX ?= /dev/ttyUSB0
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.SLAB_USBtoUART* | head -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.SLAB_USBtoUART*)))
 
 # setup serial terminal
 include $(RIOTBOARD)/Makefile.include.serial
diff --git a/boards/stm32f4discovery/Makefile.include b/boards/stm32f4discovery/Makefile.include
index a06d871f3e63997865fe767af116b63223fa840e..221cfa97578b492a6dace82dbfb196b6bb0dc4f0 100644
--- a/boards/stm32f4discovery/Makefile.include
+++ b/boards/stm32f4discovery/Makefile.include
@@ -4,7 +4,7 @@ export CPU_MODEL = stm32f407vg
 
 # set default port depending on operating system
 PORT_LINUX ?= /dev/ttyUSB0
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.SLAB_USBtoUART* | head -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.SLAB_USBtoUART*)))
 
 # setup serial terminal
 include $(RIOTBOARD)/Makefile.include.serial
diff --git a/boards/telosb/Makefile.include b/boards/telosb/Makefile.include
index 22a5df72f7b1be07fb3e745cd2a9a16426073364..6a78e3b2c8a000254731b3bc834be89ef342d4a0 100644
--- a/boards/telosb/Makefile.include
+++ b/boards/telosb/Makefile.include
@@ -4,7 +4,7 @@ export CPU_MODEL = msp430f1611
 
 # set default port depending on operating system
 PORT_LINUX ?= /dev/ttyUSB0
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.usbserial-MXV* | head -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.usbserial-MXV*)))
 # setup serial terminal
 include $(RIOTBOARD)/Makefile.include.serial
 
diff --git a/boards/weio/Makefile.include b/boards/weio/Makefile.include
index 87461024c1f7ed4330a91da246a25ea490c1343f..766053b7ca91e37052e56b775187205cdbc6bed8 100644
--- a/boards/weio/Makefile.include
+++ b/boards/weio/Makefile.include
@@ -12,7 +12,7 @@ export DEBUGGER_FLAGS =
 
 # define the default port depending on the host OS
 PORT_LINUX ?= /dev/ttyACM0
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.SLAB_USBtoUART* | head -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.SLAB_USBtoUART*)))
 
 # setup serial terminal
 include $(RIOTBOARD)/Makefile.include.serial
diff --git a/boards/wsn430-common/Makefile.include b/boards/wsn430-common/Makefile.include
index c5d09101c33ccd1b9c7bc480e6d6330f1b1976dc..9daf460eb24af5f4024f44c164f7e29a30acaf80 100644
--- a/boards/wsn430-common/Makefile.include
+++ b/boards/wsn430-common/Makefile.include
@@ -4,7 +4,7 @@ export CPU_MODEL = msp430f1611
 
 # set default port depending on operating system
 PORT_LINUX ?= /dev/ttyUSB0
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.SLAB_USBtoUART* | head -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.SLAB_USBtoUART*)))
 # setup serial terminal
 include $(RIOTBOARD)/Makefile.include.serial
 
diff --git a/boards/yunjia-nrf51822/Makefile.include b/boards/yunjia-nrf51822/Makefile.include
index cc8572b7ccbb09ae657335cf6af1a6cbc53213dc..14eaf500140682e889ceb5a65231a07a2f0846ee 100644
--- a/boards/yunjia-nrf51822/Makefile.include
+++ b/boards/yunjia-nrf51822/Makefile.include
@@ -4,7 +4,7 @@ export CPU_MODEL = nrf51x22xxaa
 
 # define the default port depending on the host OS
 PORT_LINUX ?= /dev/ttyUSB0
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.SLAB_USBtoUART* | head -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.SLAB_USBtoUART*)))
 
 # setup serial terminal
 include $(RIOTBOARD)/Makefile.include.serial
diff --git a/boards/z1/Makefile.include b/boards/z1/Makefile.include
index b909dd2e8592fb5396a62d81cd9d93a86122496c..fa3dea543cba47481ce1c9fbec6482c659c3d6d4 100644
--- a/boards/z1/Makefile.include
+++ b/boards/z1/Makefile.include
@@ -4,7 +4,7 @@ export CPU_MODEL = msp430f2617
 
 # set default port depending on operating system
 PORT_LINUX ?= /dev/ttyUSB0
-PORT_DARWIN ?= $(shell ls -1 /dev/tty.SLAB_USBtoUART* | head -n 1)
+PORT_DARWIN ?= $(firstword $(sort $(wildcard /dev/tty.SLAB_USBtoUART*)))
 # setup serial terminal
 include $(RIOTBOARD)/Makefile.include.serial