目前的 ulimit -Hn 显示的是4096
修改了 /etc/security/limits.conf 和 /etc/pam.d/common-session ，加了 session required limits.so
也无济于事，重启后还是没有变化。
服务器版ulimit -Hn 是 6万多，我想知道怎么在桌面版设置，突破这个限制？

http://askubuntu.com/questions/162229/how-do-i-increase-the-open-files-limit-for-a-non-root-user
At first I missed the wildcard on the end of /etc/pam.d/common-session* and just edited common-session, and even after a reboot it didn't work. But after adding the same line (for pam_limits.so) to common-session-noninteractive, ulimit -n displayed the new value after a fresh login (no reboot required). FWIW I was trying to change the limit for root (only). – Eric Lambart Jun 26 '14 at 18:12