???????????????git ??????????Tab????????   ????git c_
??????????????????????????
??????Linux????useradd??????????????????????????????????????Shell???治?????Tab??????????????????????л?????????????????????Root?????OK???
???????淢?????/etc/passwd???棬????????????Shell??root???????????
????Root?????/bin/bash
???????????????????/bin/sh
??????ls -l /bin/sh????
????/bin/sh -> /bin/dash
????dash??bash???????????/bin/sh???/bin/bash??
?????????ubuntu?????? sudo gedit /etc/passwd  ???????   ???????env????? shell=/bin/bash/
????hailongzhou:x:1000:1000:hailongzhou??????:/home/hailongzhou:/bin/bash
?????????shell????bash ????     /bin/sh -> /bin/dash
???????Ubuntu??/bin/sh??????????
???????????
????root@zhanghc-Ubuntu:~# cd /bin
????root@zhanghc-Ubuntu:/bin# ls -l /bin/sh
????lrwxrwxrwx 1 root root 4 2008-04-28 19:59 /bin/sh -> dash  //???λdash
????root@zhanghc-Ubuntu:/bin# ln -sf bash /bin/sh      //??????  -f??????
????root@zhanghc-Ubuntu:/bin# ls -l /bin/sh
????lrwxrwxrwx 1 root root 4 2008-05-01 22:51 /bin/sh -> bash  //????λbash??
????git ??????????????Tab????????
????bash ??dash??????
????bash - GNU Bourne-Again SHell
????dash - Debian Almquist Shell
??????????man bash  / man dash??????
????????????sh??????bash???
??????????????????????/bin/sh??????????bash?У?
?????磺ln -s /bin/bash /bin/sh
????????????????Щ???????
????sudo dpkg-reconfigure dash
??????????????????dash??????no???????
??????μ????￡? ls /bin/sh -al ?????????????/bin/bash???????