su doesn't give root acess I have an HTC Sensation and I'm using Linux on my workstation. I would like to switch S-Off on this phone.

I found documentation, but when I type su in adb I don't have root access:

shell@android:/ $ su


255|shell@android:/ $ id
uid=2000(shell) gid=2000(shell) groups=1003(graphics),1004(input),1007(log),1011(adb),1015(sdcard_rw),1028(sdcard_r),3001(net_bt_admin),3002(net_bt),3003(inet),3006(net_bw_stats) context=u:r:shell:s0
shell@android:/ $ 


Thanks for helping.
When a device is rooted entering su - in the terminal would result a root access acquiring process, which usually pops up a window asking for root permission; granting root would let su to go on (it will wait for the response, or rather wait for the operating system to allow or deny the request) and provide uid0 for you.

If your device is not rooted su cannot gain root permission since you don't have the means to allow it: root requests are automatically rejected.

I would guess your device is not (properly) rooted.