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.