hello, Gentleman

when I use sort and uniq, and input like this below, I got wrong output:

$ echo "src/scenelayer/actSceneTipLayer.lua

> src/table/checkpoint/checkPointInfo5000.lua

> src/table/checkpoint/checkPointInfo5000.lua

> src/table/fightscenecheckpoint.lua

> src/scenelayer/actSceneTipLayer.lua

> src/table/checkpoint/checkPointInfo5000.lua

> src/table/checkpoint/checkPointInfo5000.lua

> src/table/fightscenecheckpoint.lua

> "|sort -u

src/scenelayer/actSceneTipLayer.lua

src/table/checkpoint/checkPointInfo5000.lua

src/table/checkpoint/checkPointInfo5000.lua

src/table/fightscenecheckpoint.lua

no result when I use `uniq -u`

$ echo "src/scenelayer/actSceneTipLayer.lua

src/table/checkpoint/checkPointInfo5000.lua

src/table/checkpoint/checkPointInfo5000.lua

src/table/fightscenecheckpoint.lua

src/scenelayer/actSceneTipLayer.lua

src/table/checkpoint/checkPointInfo5000.lua

src/table/checkpoint/checkPointInfo5000.lua

src/table/fightscenecheckpoint.lua

"|sort| uniq -u

It appear the same on CentOS, Cygwin , and Mac OS X

I wonder whether it's my own mistake or the program goes wrong.