date - print or set the system date and time
dc - an arbitrary precision calculator
dd - convert and copy a file
ddate - converts Gregorian dates to Discordian dates
deallocvt - deallocate unused virtual consoles
declare
df - report filesystem disk space usage
dia - a diagram drawing program
diff - find differences between two files
diff3 - find differences between three files
dig - DNS lookup utility
dir - list directory contents
dircolors - color setup for ls
directomatic - Print without spooler
dirname - strip non-directory suffix from file name
dirs
disown
display
djpeg - decompress a JPEG file to an image file
dlpsh
dnsdomainname - show or set the system's host name
doexec - run an executable with an arbitrary argv[0]
domainname - show or set the system's host name
dos2unix
dprofpp - display perl profile data
du - estimate file space usage
dump-mixers - mixers - dump OSS mixer settings to standard output
dumpkeys - dump keyboard translation tables
dvdrecord - record audio or data Compact Discs and DVDs from a master
dvipdf - Convert TeX DVI file to PDF using ghostscript and dvips