DOS and UNIX commands

change directory cd cd
change file protection attrib chmod
compare files comp diff
copy file copy cp
delete directory rd rmdir
directory list dir ls
edit a file edit pico
environment set printenv
find string in file find grep
help help man
make directory md mkdir
move file move mv
rename file ren mv
show date and time date, time date
show disk space chkdsk df
show file type cat
show file by screens type filename more more
sort data sort sort

Source: Treebeard’s Unix Cheat Sheet