cp -r a b
Copy the entire contents of directory a into directory b.

cp a.txt backup
Copy the file a.txt across to the directory backup.

cp a.txt backup/a_bk.txt
Copy the file a.txt across to the directory backup and rename it a_bk.txt at the same time. If the file backup/a_bk.txt already existed then it will be overwritten without warning.

cp -i a.txt backup/a_bk.txt
The same as above but asks for confirmation before overwriting an existing file.

cp a b c d
In the above form, every parameter but the last - are the files to copy, and the last parameter - is the directory to copy the files too.

When copying more than one file you can't rename it at the same time.

mv is a clever little command that will either move a file (mv file directory), or rename it (mv oldfilename newfilename).

mv a b c work/reports
Move the files a, b, and c into the directory work/reports.

mv -i a b c work/reports
The same as above, but asks for confirmation before overwriting any existing files.

mv a.txt b.txt
Rename the file a.txt - b.txt.

rm a b c
Remove the files a, b and c.

rm -i a b c
The same as above, but asks for confirmation before removing each file - very important when removing files using wildcards!

rm -r work/reports
The r stands for "recursive" meaning every file and directory, in the directory work/reports will be removed, without warning - so be careful!