See https://github.com/PDP-10/its/blob/master/doc/DDT.md

UNAME	user name of job
JNAME	name of job
SNAME	directory name
dev:sname;fn1 fn2

DDT
===

log in/out
----------
user$U	log in as user
$$U	log out

input
-----
^Z	(not actually DDT) get attention from ITS, stop job and go to DDT
^D	flush input
DEL	delete char
^G	interrupt DDT

job control
-----------
$$V		list current jobs (:listj)
$^X.		kill current job (:kill)
job$^X		kill job
$J		switch to another job (or create)
job$J		switch to job
job$$J		change current job's name
$L file		load file
 $0L		load core
 $1L		load binary without symbols
$$L file	merge load
$Y file		dump SBLK file
 $0Y file	dump core file
$G		start at start address
addr$G		start at addr
addr$$G		set start address and start
addr$0G		set PC
insn$X		execute insn
$P		proceed running job with TTY
^P		proceed running job without TTY
^X		stop ^P'd job

prgm^H		give control to prgm, load if necessary
prgm^K		give control to prgm, load fresh copy (:retry)
:new prgm	give control to prgm, load fresh copy in new job

:lists		list symbols
$$^C		half-kill last typed symbol
symbol$K	half-kill symbol
symbol$$K	kill symbol

loc/		open location
loc[		open location numerically
loc]		open location symbolically
locTAB		deposit, open (new) right half
$/ etc.		open left half
$$/ etc.	open effective address

=		print fixed point
$=		print floating point
_		print symbolically
'		print as SIXBIT
"		print as ASCII
&		print as SQUOZE

$Q		last quantity
 $nQ		nth-last quantity
$$Q		last quantity with halves swapped
.		last address
$<cr>		pop address

files
-----
^F	list directory
dir^F	list directory dir
^R file	type out file
^R m.f.d. (file)	list directories on device
^R usr;..new. (udir)	make directory usr
$^R f1,f2	copy f1 to f2
^O file		delete file
$$^O f1,f2	rename f1 to f2
$ after a file name	print full file name

:copy		$^R
:move
:delete		^O
:link
:rename		$$^O

misc
----
:sstatus
:version
:whois user

:login	$U
:logout	$$U
:kill	$^X.
:listf	^F
:listj	$$V
:job	$J


TECO
====
$	once to terminate command
	again to send off whole command line

^L	refresh screen
ERfilename	open for reading
EI		open standard TECO output
EEfilename	write rest of file to output and rename to filename; close files
Y		kill buffer and load next page
nJ	put pointer after nth char in buffer
nL	put pointer at beginning of nth line after current
nC	move the pointer right n chars
nR	move the pointer left n chars
nD	delete next n chars
m,nK	kill chars
nK	kill to end of nth line after pointer
append L to move, K to kill, etc.
nFW	move forward to end of nth word
-nFW	move back to beginning of nth word
n:FW	move to beginning of n-1th word


MACDMP
======
fn1 fn2		clear, load, go to start
L$fn1 fn2	clear, load, set start
M$fn1 fn2	       load, set start
T$fn1 fn2	clear, load, load syms, go to DDT
N$fn1 fn2	       load, load syms, go to DDT
addr$		set start address to octal 'addr'
[0-7]$		set tape unit
G$		go to start address
D$fn1 fn2	dump core
K$fn1 fn2	delete from directory, but don't write directory
F$		print listing
I$fn1 fn2	check memory against file