All U-Boot command helps printed in response to ]help<command>:

askenv name [message] [size]
    - get environment variable 'name' from stdin (max 'size' chars)
askenv name
    - get environment variable 'name' from stdin
askenv name size
    - get environment variable 'name' from stdin (max 'size' chars)
askenv name [message] size
    - display 'message' string and get environment variable 'name'from stdin (max 'size' chars)
autoscr [addr]
    - run script starting at addr. A valid autoscr header must be present
base
    - print address offset for memory commands
base off
    - set address offset for memory commands to 'off'
bdinfo
    - No help available.
boota address disk
bootelf  [address]
    - load address of ELF image.
bootm [addr [arg ...]]
    - boot application image stored in memory
      passing arguments 'arg ...'; when booting a Linux kernel,
      'arg' can be the address of an initrd image
bootp [loadAddress] [bootfilename]
bootvx  [address]
    - load address of vxWorks ELF image.
bootd
    - No help available.
cmp [.b, .w, .l] addr1 addr2 count
    - compare memory
coninfo
cp [.b, .w, .l] source target count
    - copy memory
crc32 address count [addr]
    - compute CRC32 checksum [save at addr]
date [MMDDhhmm[[CC]YY][.ss]]
date reset
  - without arguments: print date & time
  - with numeric argument: set the system date & time
  - with 'reset' argument: reset the RTC
dcache [on, off]
    - enable or disable data (writethrough) cache
dhcp
diskboot loadAddr dev:part
echo [args..]
    - echo args to console; \c suppresses newline
erase start end
    - erase FLASH from addr 'start' to addr 'end'
erase N:SF[-SL]
    - erase sectors SF-SL in FLASH bank # N
erase bank N
    - erase FLASH bank # N
erase all
    - erase all FLASH banks
fdcboot loadAddr drive
flinfo
    - print information for all FLASH memory banks
flinfo N
    - print information for FLASH memory bank # N
go addr [arg ...]
    - start application at address 'addr'
      passing 'arg' as arguments
help [command ...]
    - show help information (for 'command')
      'help' prints online help for the monitor commands.
      Without arguments, it prints a short usage message for all commands.
      To get detailed help information for specific commands you can type
      'help' with one or more command names as arguments.
icache [on, off]
    - enable or disable instruction cache
ide reset
    - reset IDE controller
ide info
    - show available IDE devices
ide device [dev]
    - show or set current device
ide part [dev]
    - print partition table of one or all IDE devices
ide read  addr blk# cnt
ide write addr blk# cnt
    - read/write `cnt' blocks starting at block `blk#'
      to/from memory address `addr'
iminfo addr [addr ...]
    - print header information for application image starting at
      address 'addr' in memory; this includes verification of the
      image contents (magic number, header and payload checksums)
loadb [ off ] [ baud ]
    - load binary file over serial line with offset 'off' and baudrate 'baud'
loads [ off ]
    - load S-Record file over serial line with offset 'off'
loop [.b, .w, .l] address number_of_objects
    - loop on a set of addresses
md [.b, .w, .l] address [# of objects]
    - memory display
menu
mm [.b, .w, .l] address
    - memory modify, auto increment address
mtest [start [end [pattern]]]
    - simple RAM read/write test
mw [.b, .w, .l] address value [count]
    - write memory
nm [.b, .w, .l] address
    - memory modify, read and keep address
pci [bus] [long]
    - short or long list of PCI devices on bus 'bus'
pci header b.d.f
    - show header of PCI device 'bus.device.function'
pci display[.b, .w, .l] b.d.f [address] [# of objects]
    - display PCI configuration space (CFG)
pci next[.b, .w, .l] b.d.f address
    - modify, read and keep CFG address
pci modify[.b, .w, .l] b.d.f address
    -  modify, auto increment CFG address
pci write[.b, .w, .l] b.d.f address value
    - write to CFG address
post [post]
    - post diagnostic test
post [post]
    - post diagnostic test
printenv
    - print values of all environment variables
printenv name ...
    - print value of environment variable 'name'
protect on  start end
    - protect FLASH from addr 'start' to addr 'end'
protect on  N:SF[-SL]
    - protect sectors SF-SL in FLASH bank # N
protect on  bank N
    - protect FLASH bank # N
protect on  all
    - protect all FLASH banks
protect off start end
    - make FLASH from addr 'start' to addr 'end' writable
protect off N:SF[-SL]
    - make sectors SF-SL writable in FLASH bank # N
protect off bank N
    - make FLASH bank # N writable
protect off all
    - make all FLASH banks writable
rarpboot [loadAddress] [bootfilename]
reset
    - No help available.
run var [...]
    - run the commands in the environment variable(s) 'var'
saveenv - No help available.
scsiboot loadAddr dev:part
scsi reset
    - reset SCSI controller
scsi info
    - show available SCSI devices
scsi scan
    - (re-)scan SCSI bus
scsi device [dev]
    - show or set current device
scsi part [dev]
    - print partition table of one or all SCSI devices
scsi read addr blk# cnt
    - read `cnt' blocks starting at block `blk#'
      to memory address `addr'
setenv name value ...
    - set environment variable 'name' to 'value ...'
setenv name
    - delete environment variable 'name'
sleep N
    - delay execution for N seconds (N is _decimal_ !!!)
tftpboot [loadAddress] [bootfilename]
usbboot loadAddr dev:part
usb reset
    - reset (rescan) USB controller
usb stop [f]
    - stop USB [f]=force stop
usb tree
    - show USB device tree
usb info [dev]
    - show available USB devices
usb scan
    - (re-)scan USB bus for storage devices
usb device [dev]
    - show or set current USB storage device
usb part [dev]
    - print partition table of one or all USB storage devices
usb read addr blk# cnt
    - read `cnt' blocks starting at block `blk#'
      to memory address `addr'
version - No help available.