Tip #258 List non-system users
I use the following to list non-system users. It should be portable though won't work on systems without the getent command.alias lsusers='getent passwd | tr ":" " " | awk "\$3 >= $(grep UID_MIN /etc/login.defs | cut -d " " -f 2) { print \$1 }" | sort'alias aptitude at awk bash bc cal cat cd colrm comm cp csh curl cut date dd df dialog diff dirname dpkg du fc find fuser grep gs gzip history iconv kill ksh last less ln ls lsof lynx m4 md5sum mkdir mkfifo mkisofs mv mysql nc netstat openssl OSX perl ping popd ps pushd python read redirection rm scp screen sed sort ssh stat sudo svn tail tar tee test top tr uniq vim wc wget xargs