diff --git a/examples/default/Makefile b/examples/default/Makefile
index 4a6fd8ee64c0..245c9c046481 100644
--- a/examples/default/Makefile
+++ b/examples/default/Makefile
@@ -29,7 +29,6 @@ QUIET ?= 1
 
 # Modules to include:
 
-USEMODULE += uart0
 USEMODULE += shell
 USEMODULE += shell_commands
 USEMODULE += ps
diff --git a/examples/default/main.c b/examples/default/main.c
index df24568dce5c..d7ffc937f390 100644
--- a/examples/default/main.c
+++ b/examples/default/main.c
@@ -26,10 +26,8 @@
 #include <string.h>
 
 #include "thread.h"
-#include "posix_io.h"
 #include "shell.h"
 #include "shell_commands.h"
-#include "board_uart0.h"
 
 #if FEATURE_PERIPH_RTC
 #include "periph/rtc.h"
@@ -41,9 +39,6 @@
 
 int main(void)
 {
-    shell_t shell;
-    (void) posix_open(uart0_handler_pid, 0);
-
 #ifdef MODULE_LTC4150
     ltc4150_start();
 #endif
@@ -54,8 +49,8 @@ int main(void)
 
     (void) puts("Welcome to RIOT!");
 
-    shell_init(&shell, NULL, UART0_BUFSIZE, uart0_readc, uart0_putc);
+    char line_buf[SHELL_DEFAULT_BUFSIZE];
+    shell_run(NULL, line_buf, SHELL_DEFAULT_BUFSIZE);
 
-    shell_run(&shell);
     return 0;
 }
diff --git a/examples/gnrc_networking/Makefile b/examples/gnrc_networking/Makefile
index 3347e0ce677b..b42bdf10a2fb 100644
--- a/examples/gnrc_networking/Makefile
+++ b/examples/gnrc_networking/Makefile
@@ -28,8 +28,7 @@ USEMODULE += gnrc_rpl
 USEMODULE += gnrc_pktdump
 # Additional networking modules that can be dropped if not needed
 USEMODULE += gnrc_icmpv6_echo
-# Add also the shell, some shell commands (which are based on uart0 in this app)
-USEMODULE += uart0
+# Add also the shell, some shell commands
 USEMODULE += shell
 USEMODULE += shell_commands
 USEMODULE += ps
diff --git a/examples/gnrc_networking/main.c b/examples/gnrc_networking/main.c
index b686ad97e2ec..c3c66f9978a3 100644
--- a/examples/gnrc_networking/main.c
+++ b/examples/gnrc_networking/main.c
@@ -21,8 +21,6 @@
 #include <stdio.h>
 
 #include "shell.h"
-#include "board_uart0.h"
-#include "posix_io.h"
 
 extern int udp_cmd(int argc, char **argv);
 
@@ -33,15 +31,12 @@ static const shell_command_t shell_commands[] = {
 
 int main(void)
 {
-    shell_t shell;
-
     puts("RIOT network stack example application");
 
     /* start shell */
     puts("All up, running the shell now");
-    posix_open(uart0_handler_pid, 0);
-    shell_init(&shell, shell_commands, UART0_BUFSIZE, uart0_readc, uart0_putc);
-    shell_run(&shell);
+    char line_buf[SHELL_DEFAULT_BUFSIZE];
+    shell_run(shell_commands, line_buf, SHELL_DEFAULT_BUFSIZE);
 
     /* should be never reached */
     return 0;
diff --git a/tests/driver_at86rf2xx/Makefile b/tests/driver_at86rf2xx/Makefile
index 9cfba5f54dfe..1f375e39dbf2 100644
--- a/tests/driver_at86rf2xx/Makefile
+++ b/tests/driver_at86rf2xx/Makefile
@@ -65,7 +65,6 @@ USEMODULE += auto_init_gnrc_netif
 USEMODULE += gnrc_netif
 USEMODULE += gnrc_nomac
 USEMODULE += gnrc_pktdump
-USEMODULE += uart0
 USEMODULE += shell
 USEMODULE += shell_commands
 USEMODULE += ps
diff --git a/tests/driver_at86rf2xx/main.c b/tests/driver_at86rf2xx/main.c
index 40efb9bbd367..06c7bf491782 100644
--- a/tests/driver_at86rf2xx/main.c
+++ b/tests/driver_at86rf2xx/main.c
@@ -22,22 +22,14 @@
 
 #include "shell.h"
 #include "shell_commands.h"
-#include "posix_io.h"
-#include "board_uart0.h"
 #include "net/gnrc/pktdump.h"
 #include "net/gnrc.h"
 
-/**
- * @brief   Buffer size used by the shell
- */
-#define SHELL_BUFSIZE           (64U)
-
 /**
  * @brief   Maybe you are a golfer?!
  */
 int main(void)
 {
-    shell_t shell;
     gnrc_netreg_entry_t dump;
 
     puts("AT86RF2xx device driver test");
@@ -50,9 +42,9 @@ int main(void)
 
     /* start the shell */
     puts("Initialization successful - starting the shell now");
-    (void) posix_open(uart0_handler_pid, 0);
-    shell_init(&shell, NULL, SHELL_BUFSIZE, uart0_readc, uart0_putc);
-    shell_run(&shell);
+
+    char line_buf[SHELL_DEFAULT_BUFSIZE];
+    shell_run(NULL, line_buf, SHELL_DEFAULT_BUFSIZE);
 
     return 0;
 }
diff --git a/tests/driver_kw2xrf/Makefile b/tests/driver_kw2xrf/Makefile
index 81fdb4d097c0..a49920547697 100644
--- a/tests/driver_kw2xrf/Makefile
+++ b/tests/driver_kw2xrf/Makefile
@@ -54,7 +54,6 @@ USEMODULE += auto_init_gnrc_netif
 USEMODULE += gnrc_netif
 USEMODULE += gnrc_nomac
 USEMODULE += gnrc_pktdump
-USEMODULE += uart0
 USEMODULE += shell
 USEMODULE += shell_commands
 USEMODULE += ps
diff --git a/tests/driver_kw2xrf/main.c b/tests/driver_kw2xrf/main.c
index f3047dfd2bed..2591bdfdd086 100644
--- a/tests/driver_kw2xrf/main.c
+++ b/tests/driver_kw2xrf/main.c
@@ -21,19 +21,11 @@
 
 #include "shell.h"
 #include "shell_commands.h"
-#include "posix_io.h"
-#include "board_uart0.h"
 #include "net/gnrc.h"
 #include "net/gnrc/pktdump.h"
 
-/**
- * @brief   Buffer size used by the shell
- */
-#define SHELL_BUFSIZE   (64U)
-
 int main(void)
 {
-    shell_t shell;
     gnrc_netreg_entry_t dump;
 
     puts("KW2XRF device driver test");
@@ -46,9 +38,9 @@ int main(void)
 
     /* start the shell */
     puts("Initialization successful - starting the shell now");
-    (void) posix_open(uart0_handler_pid, 0);
-    shell_init(&shell, NULL, SHELL_BUFSIZE, uart0_readc, uart0_putc);
-    shell_run(&shell);
+
+    char line_buf[SHELL_DEFAULT_BUFSIZE];
+    shell_run(NULL, line_buf, SHELL_DEFAULT_BUFSIZE);
 
     return 0;
 }
diff --git a/tests/driver_netdev_eth/main.c b/tests/driver_netdev_eth/main.c
index d4d817ebe60d..f9dabde9ec07 100644
--- a/tests/driver_netdev_eth/main.c
+++ b/tests/driver_netdev_eth/main.c
@@ -33,17 +33,11 @@
 #include "net/dev_eth.h"
 #include "dev_eth_tap.h"
 
-/**
- * @brief   Buffer size used by the shell
- */
-#define SHELL_BUFSIZE           (64U)
-
 /**
  * @brief   Maybe you are a golfer?!
  */
 int main(void)
 {
-    shell_t shell;
     gnrc_netreg_entry_t dump;
 
     puts("netdev ethernet device driver test");
@@ -60,8 +54,8 @@ int main(void)
     gnrc_netreg_register(GNRC_NETTYPE_UNDEF, &dump);
 
     /* start the shell */
-    shell_init(&shell, NULL, SHELL_BUFSIZE, getchar, putchar);
-    shell_run(&shell);
+    char line_buf[SHELL_DEFAULT_BUFSIZE];
+    shell_run(NULL, line_buf, SHELL_DEFAULT_BUFSIZE);
 
     return 0;
 }
diff --git a/tests/driver_nrf24l01p_lowlevel/main.c b/tests/driver_nrf24l01p_lowlevel/main.c
index 4913d89ffa04..42c8e7629c72 100644
--- a/tests/driver_nrf24l01p_lowlevel/main.c
+++ b/tests/driver_nrf24l01p_lowlevel/main.c
@@ -51,8 +51,6 @@
 
 #define TEST_RX_MSG                1
 
-#define SHELL_BUFFER_SIZE        128
-
 static int cmd_send(int argc, char **argv);
 static int cmd_print_regs(int argc, char **argv);
 static int cmd_its(int argc, char **argv);
@@ -325,14 +323,10 @@ int cmd_print_regs(int argc, char **argv)
 
 int main(void)
 {
-    shell_t shell;
-
     puts("Welcome to RIOT!");
 
-    puts("Initializing shell...");
-    shell_init(&shell, shell_commands, SHELL_BUFFER_SIZE, getchar, putchar);
-
     puts("Starting shell...");
-    shell_run(&shell);
+    char line_buf[SHELL_DEFAULT_BUFSIZE];
+    shell_run(shell_commands, line_buf, SHELL_DEFAULT_BUFSIZE);
     return 0;
 }
diff --git a/tests/driver_nrfmin/Makefile b/tests/driver_nrfmin/Makefile
index b082b0dbd124..11b3bba8e99d 100644
--- a/tests/driver_nrfmin/Makefile
+++ b/tests/driver_nrfmin/Makefile
@@ -6,7 +6,6 @@ FEATURES_REQUIRED = radio_nrfmin
 USEMODULE += shell
 USEMODULE += shell_commands
 USEMODULE += ps
-USEMODULE += uart0
 USEMODULE += radio_nrfmin
 USEMODULE += gnrc
 USEMODULE += gnrc_nomac
diff --git a/tests/driver_nrfmin/main.c b/tests/driver_nrfmin/main.c
index 3ad26ecb6948..5dadfc3bd4c1 100644
--- a/tests/driver_nrfmin/main.c
+++ b/tests/driver_nrfmin/main.c
@@ -21,20 +21,15 @@
 #include <stdio.h>
 
 #include "shell.h"
-#include "posix_io.h"
-#include "board_uart0.h"
 #include "nrfmin.h"
 #include "net/gnrc.h"
 #include "net/gnrc/nomac.h"
 #include "net/gnrc/pktdump.h"
 
-#define SHELL_BUFSIZE       (UART0_BUFSIZE)
-
 static char nomac_stack[THREAD_STACKSIZE_DEFAULT];
 
 int main(void)
 {
-    shell_t shell;
     gnrc_netdev_t dev;
     gnrc_netreg_entry_t netobj;
 
@@ -51,10 +46,8 @@ int main(void)
     gnrc_netreg_register(GNRC_NETTYPE_UNDEF, &netobj);
 
     /* initialize and run the shell */
-    board_uart0_init();
-    posix_open(uart0_handler_pid, 0);
-    shell_init(&shell, NULL, SHELL_BUFSIZE, uart0_readc, uart0_putc);
-    shell_run(&shell);
+    char line_buf[SHELL_DEFAULT_BUFSIZE];
+    shell_run(NULL, line_buf, SHELL_DEFAULT_BUFSIZE);
 
     return 0;
 }
diff --git a/tests/driver_pcd8544/Makefile b/tests/driver_pcd8544/Makefile
index 9bd3beef35d2..e83de301f7c6 100644
--- a/tests/driver_pcd8544/Makefile
+++ b/tests/driver_pcd8544/Makefile
@@ -3,7 +3,6 @@ include ../Makefile.tests_common
 
 FEATURES_REQUIRED = periph_gpio periph_spi
 
-USEMODULE += uart0
 USEMODULE += shell
 USEMODULE += pcd8544
 
diff --git a/tests/driver_pcd8544/main.c b/tests/driver_pcd8544/main.c
index 56bbcf2ca6ad..58d6453f47a9 100644
--- a/tests/driver_pcd8544/main.c
+++ b/tests/driver_pcd8544/main.c
@@ -35,13 +35,9 @@
 #include <string.h>
 #include <stdlib.h>
 
-#include "posix_io.h"
-#include "board_uart0.h"
 #include "shell.h"
 #include "pcd8544.h"
 
-#define SHELL_BUFSIZE           (64U)
-
 static pcd8544_t dev;
 
 static int _contrast(int argc, char **argv)
@@ -158,8 +154,6 @@ static const shell_command_t shell_commands[] = {
 
 int main(void)
 {
-    shell_t shell;
-
     puts("PCD8544 LCD display test application\n");
     printf("Initializing PCD8544 LCD at SPI_%i... ", TEST_PCD8544_SPI);
     if (pcd8544_init(&dev, TEST_PCD8544_SPI, TEST_PCD8544_CS,
@@ -170,9 +164,9 @@ int main(void)
 
     /* run shell */
     puts("All OK, running shell now");
-    (void) posix_open(uart0_handler_pid, 0);
-    shell_init(&shell, shell_commands, SHELL_BUFSIZE, uart0_readc, uart0_putc);
-    shell_run(&shell);
+
+    char line_buf[SHELL_DEFAULT_BUFSIZE];
+    shell_run(shell_commands, line_buf, SHELL_DEFAULT_BUFSIZE);
 
     return 0;
 }
diff --git a/tests/driver_xbee/main.c b/tests/driver_xbee/main.c
index 22e0ffea8ddd..bf0641ae67cc 100644
--- a/tests/driver_xbee/main.c
+++ b/tests/driver_xbee/main.c
@@ -25,17 +25,11 @@
 #include "net/gnrc.h"
 #include "net/gnrc/pktdump.h"
 
-/**
- * @brief   Buffer size used by the shell
- */
-#define SHELL_BUFSIZE           (64U)
-
 /**
  * @brief   Maybe you are a golfer?!
  */
 int main(void)
 {
-    shell_t shell;
     gnrc_netreg_entry_t dump;
 
     puts("Xbee S1 device driver test");
@@ -51,8 +45,9 @@ int main(void)
 
     /* start the shell */
     puts("Initialization OK, starting shell now");
-    shell_init(&shell, NULL, SHELL_BUFSIZE, getchar, putchar);
-    shell_run(&shell);
+
+    char line_buf[SHELL_DEFAULT_BUFSIZE];
+    shell_run(NULL, line_buf, SHELL_DEFAULT_BUFSIZE);
 
     return 0;
 }
diff --git a/tests/periph_gpio/Makefile b/tests/periph_gpio/Makefile
index d987ff764639..e71e3a0fc8aa 100644
--- a/tests/periph_gpio/Makefile
+++ b/tests/periph_gpio/Makefile
@@ -3,7 +3,6 @@ include ../Makefile.tests_common
 
 FEATURES_REQUIRED = periph_gpio
 
-USEMODULE += uart0
 USEMODULE += shell
 
 include $(RIOTBASE)/Makefile.include
diff --git a/tests/periph_gpio/main.c b/tests/periph_gpio/main.c
index b34f65d98fae..685e3a82f595 100644
--- a/tests/periph_gpio/main.c
+++ b/tests/periph_gpio/main.c
@@ -22,13 +22,9 @@
 #include <stdlib.h>
 
 #include "shell.h"
-#include "posix_io.h"
-#include "board_uart0.h"
 #include "periph/gpio.h"
 #include "hwtimer.h"
 
-#define SHELL_BUFSIZE       (64U)
-
 static void cb(void *arg)
 {
     printf("INT: external interrupt from pin %i\n", (int)arg);
@@ -237,8 +233,6 @@ static const shell_command_t shell_commands[] = {
 
 int main(void)
 {
-    shell_t shell;
-
     puts("GPIO peripheral driver test\n");
     puts("In this test, pins are specified by integer port and pin numbers.\n"
          "So if your platform has a pin PA01, it will be port=0 and pin=1,\n"
@@ -247,9 +241,8 @@ int main(void)
          "      behavior for not existing ports/pins is not defined!");
 
     /* start the shell */
-    (void) posix_open(uart0_handler_pid, 0);
-    shell_init(&shell, shell_commands, SHELL_BUFSIZE, uart0_readc, uart0_putc);
-    shell_run(&shell);
+    char line_buf[SHELL_DEFAULT_BUFSIZE];
+    shell_run(shell_commands, line_buf, SHELL_DEFAULT_BUFSIZE);
 
     return 0;
 }
diff --git a/tests/periph_i2c/Makefile b/tests/periph_i2c/Makefile
index 91eb06be1b30..56e66531fd63 100644
--- a/tests/periph_i2c/Makefile
+++ b/tests/periph_i2c/Makefile
@@ -4,6 +4,5 @@ include ../Makefile.tests_common
 FEATURES_REQUIRED = periph_i2c
 
 USEMODULE += shell
-USEMODULE += uart0
 
 include $(RIOTBASE)/Makefile.include
diff --git a/tests/periph_i2c/main.c b/tests/periph_i2c/main.c
index a01780fff442..cd6226ab979c 100644
--- a/tests/periph_i2c/main.c
+++ b/tests/periph_i2c/main.c
@@ -24,8 +24,6 @@
 #include "periph_conf.h"
 #include "periph/i2c.h"
 #include "shell.h"
-#include "posix_io.h"
-#include "board_uart0.h"
 
 #define BUFSIZE        (128U)
 
@@ -306,17 +304,11 @@ static const shell_command_t shell_commands[] = {
 
 int main(void)
 {
-    shell_t shell;
-
     puts("Test for the low-level I2C driver");
 
-    /* prepare I/O for shell */
-    board_uart0_init();
-    (void) posix_open(uart0_handler_pid, 0);
-
     /* define own shell commands */
-    shell_init(&shell, shell_commands, UART0_BUFSIZE, uart0_readc, uart0_putc);
-    shell_run(&shell);
+    char line_buf[SHELL_DEFAULT_BUFSIZE];
+    shell_run(shell_commands, line_buf, SHELL_DEFAULT_BUFSIZE);
 
     return 0;
 }
diff --git a/tests/periph_spi/main.c b/tests/periph_spi/main.c
index 8e2196621c82..c04a20bdfa93 100644
--- a/tests/periph_spi/main.c
+++ b/tests/periph_spi/main.c
@@ -29,8 +29,6 @@
 #include "periph/spi.h"
 #include "periph/gpio.h"
 
-#define SHELL_BUFSIZE       (128U)
-
 enum {
     READ = 0,
     WRITE,
@@ -288,15 +286,13 @@ static const shell_command_t shell_commands[] = {
 
 int main(void)
 {
-    shell_t shell;
-
     puts("\nRIOT low-level SPI driver test");
     puts("This application enables you to test a platforms SPI driver implementation.");
     puts("Enter 'help' to get started\n");
 
     /* run the shell */
-    shell_init(&shell, shell_commands, SHELL_BUFSIZE, getchar, putchar);
-    shell_run(&shell);
+    char line_buf[SHELL_DEFAULT_BUFSIZE];
+    shell_run(shell_commands, line_buf, SHELL_DEFAULT_BUFSIZE);
 
     return 0;
 }
diff --git a/tests/shell/Makefile b/tests/shell/Makefile
index bf0b3d724304..721a5f89d29e 100644
--- a/tests/shell/Makefile
+++ b/tests/shell/Makefile
@@ -4,7 +4,6 @@ include ../Makefile.tests_common
 USEMODULE += shell
 USEMODULE += shell_commands
 USEMODULE += ps
-USEMODULE += uart0
 
 DISABLE_MODULE += auto_init
 
diff --git a/tests/shell/ReadMe.txt b/tests/shell/ReadMe.txt
index d2f8288419ab..16bf30e2416f 100644
--- a/tests/shell/ReadMe.txt
+++ b/tests/shell/ReadMe.txt
@@ -1,15 +1,14 @@
 This application shows how to use own or the system shell commands. In order to use
 the system shell commands:
 
-1. Additionally to the module: shell, shell_commands and posix,
+1. Additionally to the module: shell, shell_commands,
    the module for the corresponding system command is to include, e.g.
    module ps for the ps command (cf. the Makefile in the application root
    directory).
-2. The shell must be initialized as follows:
-        2.1 shell_t sys_shell;
-        2.2 shell_init(&shell, shell_commands, shell_bufsize, shell_readc,
-                       shell_putchar);
-            or shell_init(&sys_shell, NULL, shell_bufsize,
-                          shell_readc, shell_putchar);
-            /* to initialize without the built-in shell commands */
-        2.3 shell_run(&sys_shell);
+2. Start the shell like this:
+    2.1 reserve buffer:
+        char line_buf[SHELL_DEFAULT_BUFSIZE];
+    2.1a run shell only with system commands:
+        shell_run(NULL, line_buf, SHELL_DEFAULT_BUFSIZE);
+    2.1b run shell with provided commands in addition to system commands:
+        shell_run(shell_commands, line_buf, SHELL_DEFAULT_BUFSIZE);
diff --git a/tests/shell/main.c b/tests/shell/main.c
index 7bd4850f47e4..c4d59cb77a27 100644
--- a/tests/shell/main.c
+++ b/tests/shell/main.c
@@ -22,11 +22,7 @@
 #include <string.h>
 
 #include "shell_commands.h"
-#include "posix_io.h"
 #include "shell.h"
-#include "board_uart0.h"
-
-#define SHELL_BUFSIZE   (UART0_BUFSIZE)
 
 static int print_teststart(int argc, char **argv)
 {
@@ -68,20 +64,16 @@ int main(void)
 
     printf("test_shell.\n");
 
-    board_uart0_init();
 
-    posix_open(uart0_handler_pid, 0);
+    /* define buffer to be used by the shell */
+    char line_buf[SHELL_DEFAULT_BUFSIZE];
 
     /* define own shell commands */
-    shell_t shell;
-    shell_init(&shell, shell_commands, SHELL_BUFSIZE, getchar, putchar);
-    shell_run(&shell);
+    shell_run(shell_commands, line_buf, SHELL_DEFAULT_BUFSIZE);
 
     /* or use only system shell commands */
     /*
-    shell_t sys_shell;
-    shell_init(&sys_shell, NULL, SHELL_BUFSIZE, shell_readc, shell_putchar);
-    shell_run(&sys_shell);
+    shell_run(NULL, line_buf, SHELL_DEFAULT_BUFSIZE);
     */
 
     return 0;
diff --git a/tests/slip/main.c b/tests/slip/main.c
index 4958789d6a97..a600fa2a5479 100644
--- a/tests/slip/main.c
+++ b/tests/slip/main.c
@@ -25,17 +25,11 @@
 #include "net/gnrc.h"
 #include "net/gnrc/pktdump.h"
 
-/**
- * @brief   Buffer size used by the shell
- */
-#define SHELL_BUFSIZE           (64U)
-
 /**
  * @brief   Maybe you are a golfer?!
  */
 int main(void)
 {
-    shell_t shell;
     gnrc_netreg_entry_t dump;
 
     puts("SLIP test");
@@ -53,8 +47,9 @@ int main(void)
 
     /* start the shell */
     puts("Initialization OK, starting shell now");
-    shell_init(&shell, NULL, SHELL_BUFSIZE, getchar, putchar);
-    shell_run(&shell);
+
+    char line_buf[SHELL_DEFAULT_BUFSIZE];
+    shell_run(NULL, line_buf, SHELL_DEFAULT_BUFSIZE);
 
     return 0;
 }
diff --git a/tests/struct_tm_utility/Makefile b/tests/struct_tm_utility/Makefile
index 6882bf4b165e..4a9db06daf03 100644
--- a/tests/struct_tm_utility/Makefile
+++ b/tests/struct_tm_utility/Makefile
@@ -4,7 +4,6 @@ include ../Makefile.tests_common
 DISABLE_MODULE += auto_init
 
 USEMODULE += shell
-USEMODULE += uart0
 USEMODULE += timex
 
 # The MSP-430 toolchain lacks sscanf:
diff --git a/tests/struct_tm_utility/main.c b/tests/struct_tm_utility/main.c
index bf2791d10507..eb9176a94e7a 100644
--- a/tests/struct_tm_utility/main.c
+++ b/tests/struct_tm_utility/main.c
@@ -30,12 +30,8 @@
 #include <stdbool.h>
 
 #include "shell.h"
-#include "posix_io.h"
-#include "board_uart0.h"
 #include "tm.h"
 
-#define SHELL_BUFSIZE (UART0_BUFSIZE)
-
 static const char MON_NAMES[12][3] = {
     "JAN", "FEB", "MAR", "APR",
     "MAY", "JUN", "JUL", "AUG",
@@ -136,14 +132,10 @@ static const shell_command_t shell_commands[] = {
 
 int main(void)
 {
-    board_uart0_init();
-    posix_open(uart0_handler_pid, 0);
-
-    shell_t shell;
-    shell_init(&shell, shell_commands, SHELL_BUFSIZE, uart0_readc, uart0_putc);
-
     puts("`struct tm` utility shell.");
-    shell_run(&shell);
+
+    char line_buf[SHELL_DEFAULT_BUFSIZE];
+    shell_run(shell_commands, line_buf, SHELL_DEFAULT_BUFSIZE);
 
     return 0;
 }
diff --git a/tests/zep/main.c b/tests/zep/main.c
index ab0cdff26d8e..da9aacbed43c 100644
--- a/tests/zep/main.c
+++ b/tests/zep/main.c
@@ -25,33 +25,11 @@
 #include "net/gnrc.h"
 #include "net/gnrc/pktdump.h"
 
-/**
- * @brief   Buffer size used by the shell
- */
-#define SHELL_BUFSIZE           (64U)
-
-/**
- * @brief   Read chars from STDIO
- */
-int shell_read(void)
-{
-    return (int)getchar();
-}
-
-/**
- * @brief   Write chars to STDIO
- */
-void shell_put(int c)
-{
-    putchar((char)c);
-}
-
 /**
  * @brief   Maybe you are a golfer?!
  */
 int main(void)
 {
-    shell_t shell;
     gnrc_netreg_entry_t dump;
 
     puts("ZEP module test");
@@ -69,8 +47,8 @@ int main(void)
 
     /* start the shell */
     puts("Initialization OK, starting shell now");
-    shell_init(&shell, NULL, SHELL_BUFSIZE, getchar, putchar);
-    shell_run(&shell);
+    char line_buf[SHELL_DEFAULT_BUFSIZE];
+    shell_run(NULL, line_buf, SHELL_DEFAULT_BUFSIZE);
 
     return 0;
 }