NMI menu
Pressing the NMI button will bring up the NMI file selector menu.
From that menu the following keyboard shortcuts can be used.

Up, Down
Move cursor on page

Left, Right
Change page

Enter
RUN .sna, .z80, files with ZX header of type 'basic', view screen (same as 'v' except for .sna files), attach .tap file to input slot and soft reset with autoload

r
Reset(Warm)

s
Create snapshot (auto incrementing name starting with snap0000.sna on initialisation of ESXDOS).
If you get ERROR 18 it’s because file already exists, try again.

1
Go to parent directory (chdir to ‘..’)

v
Show screen from .scr and .sna files (or files with ZX header of type ‘CODE’)

i
Attach tape file to input slot

Space
Exit from NMI mode

H
Onscreen help

BASIC commands
On all BASIC commands that use a drive parameter, you can use * for the current drive.
[…] means its an optional parameters.

GOTO [drive] ["path"]
Example:
GOTO hd0"demos"
This will change the current drive and directory to hd0:/demos.
You can use it to change the current drive, dir, or both.

CAT [drive]
Example:
CAT, CAT *, CAT hd1
Without specifying a drive a fast CAT is done (no speccy header info is displayed).

LOAD drive "path/filename" [CODE]|[SCREEN$]
MERGE drive "path/filename"
Example:
LOAD *"/test/blabla", etc

SAVE drive "path/filename" [LINE]|[CODE]|[SCREEN$]
Example:
SAVE *"filename" SCREEN$, etc

ERASE [drive] "path/filename"
Example:
ERASE "filename", ERASE *"filename", etc

System commands
Files located in the /BIN directory are system commands. These system commands can be executed from BASIC by typing: ".command <args>".

Each .command has 7.5K of RAM available and may call any ESXDOS syscall.
Commands can also exit to BASIC with a custom error message.

Most commands are self-explanatory or show onscreen help when run without arguments (or with the -h parameter).
An example of the onscreen help:
.tapeout
tapeOUT v0.1 (c) phoenix

Usage: tapeout [args] [tapfile]

-c: Close file
-o: Overwrite file

.ls
Show directory listing

.cd somedir
Change directory

.tapein somefile.tap
Attach .tap file for reading

.tapeout somefile.tap
Attach .tap file for writing

.chmod +h somefile.sys
Set/unset attributes on file/dir

.mkdir newdir
Create a new directory

.mv oldname newname
Rename/move file/dir

.cp source target
Copy file

.more textfile
Display the contents of a textfile

New commands in v0.8.5:
.divideo
.vdisk
.playwav
.dskprobe
.snapload
.gramon
.speakcz

TR-DOS emulator
Either use the NMI browser to attach/auto-LOAD .TRDs, or use the .vdisk command:
.vdisk unit <filename>

Unit 0 = Drive A, Unit 1 = Drive B, etc.
If you specify just the unit, it will eject the virtual drive.
You can use .dskprobe to check the contents of the vdisk.
Instructions on how to use TR-DOS are out of the scope of this document.

Note: TR-DOS emulation is not available in MapRAM mode (BETADISK.SYS will not be loaded)