Moved du back seperate pages for linux/osx because GNU has --max-depth, BSD has -d
Edited the examples to always explicitly specify unit as previous examples allowed return of block units which is probably not what your average user wants.
A bunch of new pages:
common/: dig, gzip, rm, sort, zfs, zpool
linux/: apt-get, shutdown
osx/: airport, caffeinate, diskutil, networksetup open, pgrep, qlmanage, say, shutdown, sysctl, system_profiler

Edits to existing pages:
curl: Added simple download example
find: Added iname and size exmaples
grep: Edited -c description
ps: Added wide lines example
ssh: edited -D description, added simple port forwarding example
unzip: added list option