?18? ?7? Shell???? 7.2???? 7.2.3?????? 7.2.4 ??????

1
?18??7? Shell????7.2???? 7.2.3??????7.2.4
??????
2
? ?

• ??????????
• ???????????
• ???????????

3
???3????

• Geecy???????????Tom???????????????tom_at_geecy??
  ????Tom????tom_at_geecy????????,???????MS-DOS??????
  ,??C\Dos6.22gt?

4
???3????(?)

• ??,Tom??????????????????????????????????
• 0206pm /usr/bin gt

5
???3???

• Shell????????
• ??????????,?????????
• ???????????,?????????????
• ???????????????????,??????????,????????????????

6
???3???(?)

• ????????????,????????????????????????????????,????
  ?????,?????????????

7
7.2.3 ??????

• ????????linux??,????????????shell,????shell(login
  shell)?
• ???linux???,?????????shell??????????????shell,????
  ?shell?
• ??shell?????,???????????????,??????(Environment
  Variable)

8
7.2.3 ??????

• ??????env????????????????????????

9
7.2.3 ??????

• ??set???????????????

10
7.2.3 ??????(?)

• 1?LOGNAME??
• ???????????????????echo??????????
• 2?SHELL??
• ???????????shell?????echo??????????

11
7.2.3 ??????(?)

• 3?HOME??
• LINUX????????????????
• ???????,???????????????????????
• ??????????????HOME???,???????echo???

12
7.2.3 ??????(?)

• 4?PATH??
• ??????????????????
• ?????????,????????????,?????PATH??????????,???????
  ??????????????????,??????????
• ??,?????PATH???????????????????????,??????????

13
7.2.3 ??????(?)

• 4?PATH??(?)
• ??????echo??????????
• ?????PATH??????????????
• ??????,????????????????????bin???
• ?????????????(??chmod ux,???x????????)???????,???
  ????????????,?????????./????

14
7.2.3 ??????(?)

• 5?SHLVL??
• ??????????shell???(shell level)?
• ?LINUX?,???????SHELL????SHELL,????SHELL?????SHELL,
  ?????
• ??????????SHELL?????????
• ??SHELL????1????????SHELL?,??????1?

15
7.2.3 ??????(?)

• 6?PS1??
• PS1(Prompt String 1)???????shell?????
• \u???????
• \h??????
• \w????????????????????????\W?????
• ?????????,???????,??,\?????????,?????????
• ????PS1?????????????

16
7.2.4 ??????1?????

• ???shell??????,?????????,?????????shell????
• ?????,??shell????SHELL????????????,???????
• ?????????????????shell???????????,????????(Local
  Variable)?

17
7.2.4 ??????1?????

• 1???,??????Shell(?1?)???????COLOR,??blue?
• 2?????????SHELL(?2?) ,????SHELL???????SHELL,??SHEL
  L?,????COLOR??????,????COLOR????????SHELL???
• 3??????SHELL???????COLOR,??green?????????SHELL???
  ?COLOR???green
• 4???,??????SHELL,?????SHELL,????COLOR???,???blue,?
  ??????SHELL??????

??
18
7.2.4 ??????2?????

• ?shell???,????(Global Variable)?????????????shell?
  ?,?shell???????????
• ?????,????????SHELL,?????SHELL?,??????????SHELL???
  ?
• ??????export???????????????????

19
7.2.4 ??????2?????

• 1???,??????SHELL???????COLOR,??blue,???export?????
  ?COLOR,?????????
• 2?????????SHELL(?2?) ,????SHELL???????SHELL,??SHEL
  L?,????COLOR?????blue,????COLOR??????SHELL?
• 3??????SHELL?????COLOR????green?????????SHELL????
  COLOR???green
• 4???,??????SHELL,?????SHELL,????COLOR???,???blue,?
  ??????SHELL????????SHELL????????????????

20
???3??????

• ??????,????PS1????????????????,
  \w??????????????????????,?????????
• ???man bash?bash???,????5000??,????/PS1??????
  PS1???,??????/????,???????????PS1????

21
???3??????

• ???????,??/PROMPTING????,????????????????
• ?????????????
• ??????????????,?q???

22
???3??????

• ??man???????????

tom_at_geecy PS1"\_at_ \w gt"? 0206pm gt cd /usr/bin? 0206pm /usr/bin gt
23
? ?

• 1?Tenny?????????,?????????/usr/bin?????
• bin
• ???????/usr/local/sbin?????
• sbin