diff --git a/tests/driver_netdev_eth/main.c b/tests/driver_netdev_eth/main.c
index 89cd0affd0..0f200b096c 100644
--- a/tests/driver_netdev_eth/main.c
+++ b/tests/driver_netdev_eth/main.c
@@ -38,22 +38,6 @@
  */
 #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?!
  */
@@ -76,7 +60,7 @@ int main(void)
     ng_netreg_register(NG_NETTYPE_UNDEF, &dump);
 
     /* start the shell */
-    shell_init(&shell, NULL, SHELL_BUFSIZE, shell_read, shell_put);
+    shell_init(&shell, NULL, SHELL_BUFSIZE, getchar, putchar);
     shell_run(&shell);
 
     return 0;
diff --git a/tests/driver_nrf24l01p_lowlevel/main.c b/tests/driver_nrf24l01p_lowlevel/main.c
index 59c577bdea..37ad5297a9 100644
--- a/tests/driver_nrf24l01p_lowlevel/main.c
+++ b/tests/driver_nrf24l01p_lowlevel/main.c
@@ -327,23 +327,6 @@ int cmd_print_regs(int argc, char **argv)
     return 0;
 }
 
-
-/**
- * @brief proxy for reading a char from std-in and passing it to the shell
- */
-int shell_read(void)
-{
-    return (int) getchar();
-}
-
-/**
- * @brief proxy for taking a character from the shell and writing it to std-out
- */
-void shell_write(int c)
-{
-    putchar((char)c);
-}
-
 int main(void)
 {
     shell_t shell;
@@ -351,8 +334,7 @@ int main(void)
     puts("Welcome to RIOT!");
 
     puts("Initializing shell...");
-    shell_init(&shell, shell_commands, SHELL_BUFFER_SIZE, shell_read,
-               shell_write);
+    shell_init(&shell, shell_commands, SHELL_BUFFER_SIZE, getchar, putchar);
 
     puts("Starting shell...");
     shell_run(&shell);
diff --git a/tests/driver_xbee/main.c b/tests/driver_xbee/main.c
index a0429ab0fb..a95c0f0dfd 100644
--- a/tests/driver_xbee/main.c
+++ b/tests/driver_xbee/main.c
@@ -30,22 +30,6 @@
  */
 #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?!
  */
@@ -67,7 +51,7 @@ int main(void)
 
     /* start the shell */
     puts("Initialization OK, starting shell now");
-    shell_init(&shell, NULL, SHELL_BUFSIZE, shell_read, shell_put);
+    shell_init(&shell, NULL, SHELL_BUFSIZE, getchar, putchar);
     shell_run(&shell);
 
     return 0;
diff --git a/tests/periph_spi/main.c b/tests/periph_spi/main.c
index cef61c8779..36eead7cc4 100644
--- a/tests/periph_spi/main.c
+++ b/tests/periph_spi/main.c
@@ -274,16 +274,6 @@ int cmd_print(int argc, char **argv)
     return 0;
 }
 
-int shell_getchar(void)
-{
-    return (int)getchar();
-}
-
-void shell_putchar(int c)
-{
-    putchar((char)c);
-}
-
 static const shell_command_t shell_commands[] = {
     { "init_master", "Initialize node as SPI master", cmd_init_master },
     { "init_slave", "Initialize node as SPI slave", cmd_init_slave },
@@ -301,7 +291,7 @@ int main(void)
     puts("Enter 'help' to get started\n");
 
     /* run the shell */
-    shell_init(&shell, shell_commands, SHELL_BUFSIZE, shell_getchar, shell_putchar);
+    shell_init(&shell, shell_commands, SHELL_BUFSIZE, getchar, putchar);
     shell_run(&shell);
 
     return 0;