sh: Add `echo` command

applications/sh/commands/commands.asm

@@ -26,6 +26,11 @@ shell_parse_command:
     call compare_string
     ifz jmp shell_diskrm_command
 
+    ; echo
+    mov r1, shell_echo_command_string
+    call compare_string
+    ifz jmp shell_echo_command
+
     ; exit
     mov r1, shell_exit_command_string
     call compare_string
@@ -72,6 +77,7 @@ shell_invalid_command_string: data.str "invalid command or FXF binary" data.8 10
     #include "commands/dir.asm"
     #include "commands/disk.asm"
     #include "commands/diskrm.asm"
+    #include "commands/echo.asm"
     #include "commands/exit.asm"
     #include "commands/help.asm"
     #include "commands/rdall.asm"

applications/sh/commands/echo.asm

@@ -0,0 +1,11 @@
+; clear command
+
+shell_echo_command_string: data.strz "echo"
+
+shell_echo_command:
+    mov r0, [shell_args_ptr]
+    call print_str_to_terminal
+    mov r0, 10
+    call print_character_to_terminal
+
+    ret

applications/sh/commands/help.asm

@@ -20,6 +20,7 @@ shell_help_text:
     data.str "dir     | show contents of selected disk" data.8 10
     data.str "disk    | select disk $0" data.8 10
     data.str "diskrm  | remove disk $0" data.8 10
+    data.str "echo    | print the specified text" data.8 10
     data.str "exit    | exit the shell" data.8 10
     data.str "help    | show this help text" data.8 10
     data.str "rdall   | redirect all IO to $0" data.8 10