|df -n (or fstyp device)||show type of file system (ufs/vxfs)|
|fuser and pfiles||open files|
|prtconf -V||OBP level|
|pgrep, pkill, prstat -a||process info and manipulation|
|logins -p|-d||local users without passwords | duplicate uids|
|mpstat, prtdiag, psrinfo -v||processor information and more|
|traceroute||since Solaris 7|
|troff -man man.1 | dpost | lp||print old style man pages|
|sgml2roff lpfilter.1m | troff -man | dpost | lp||print sgml (new) man pages|
|fstyp -v||list superblock including minfree %|
|tput||nice screen output|
|what, ldd, strings||information about binaries|
|ctrl-V in vi||insert control character|
|ftp> get README | more|
|ufsdump 0f - /filesystem | (cd /mnt; ufsrestore rf -); rm /mnt/restoresymtable||dump restore pipe|
|echo \007||get bell to ring|
|comm||common (non-common) lines from two files|
|pkgchk -lp /usr/bin/ls||which package does ls belong to?|
|df -oi -F ufs||free inodes|
|icheck -b blockno filesystem||block to file mapping|
|dircmp, rsync, filesync||compare directories, sync utilities|
|nohup /var/tmp/myscript.ksh > /var/tmp/myscript.out &||for things which have to complete (no risk of terminal being logged out)|
|netstat -pn||arp like output when name services are down|
|pwdx, pldd, ptree||and more in /usr/proc/bin|
|uname -X||basic system information - one item on each line (useful for scripts)|
|read||read a line|
|listusers||another way of listing users|
|nfsstat -m (or check /etc/rmtab)||current nfs mount|
|clear_locks||clear nfs locks|
|df -h, du -h, ls -lh||since Solaris 9 - output in powers of 1024|
There is also another site which allows you to search various commands within different operating system. Unfortunately, you need to know the key word to search.
Here is another reference useful for Solaris.
This one is not as good but have some information I did not see above.
Here is a quick Reference for AIX.
A similar list for AIX so there might some overlap here.
Alternatively, you can refer to the AIX 4.3 reference book here.
Another good source for AIX information is from IBM's own System Magazine.
Finally, here is a chart of the various commands in different Unix platforms: