修改文档中的某一行 inittab

o8xv0123

1. #
   
2. # inittab       This file describes how the INIT process should set up
   
3. #               the system in a certain run-level.
   
4. #
   
5. # Author:       Miquel van Smoorenburg, <miquels@drinkel.nl.mugnet.org>
   
6. #               Modified for RHS Linux by Marc Ewing and Donnie Barnes
   
7. #
   
8. 
   
9. # Default runlevel. The runlevels used by RHS are:
   
10. #   0 - halt (Do NOT set initdefault to this)
    
11. #   1 - Single user mode
    
12. #   2 - Multiuser, without NFS (The same as 3, if you do not have networking)
    
13. #   3 - Full multiuser mode
    
14. #   4 - unused
    
15. #   5 - X11
    
16. #   6 - reboot (Do NOT set initdefault to this)
    
17. #
    
18. id:5:initdefault:
    
19. 
    
20. # System initialization.
    
21. si::sysinit:/etc/rc.d/rc.sysinit
    
22. 
    
23. l0:0:wait:/etc/rc.d/rc 0
    
24. l1:1:wait:/etc/rc.d/rc 1
    
25. l2:2:wait:/etc/rc.d/rc 2
    
26. l3:3:wait:/etc/rc.d/rc 3
    
27. l4:4:wait:/etc/rc.d/rc 4
    
28. l5:5:wait:/etc/rc.d/rc 5
    
29. l6:6:wait:/etc/rc.d/rc 6
    
30. 
    
31. # Trap CTRL-ALT-DELETE
    
32. ca::ctrlaltdel:/sbin/shutdown -t3 -r now
    
33. 
    
34. # When our UPS tells us power has failed, assume we have a few minutes
    
35. # of power left.  Schedule a shutdown for 2 minutes from now.
    
36. # This does, of course, assume you have powerd installed and your
    
37. # UPS connected and working correctly.  
    
38. pf::powerfail:/sbin/shutdown -f -h +2 "Power Failure; System Shutting Down"
    
39. 
    
40. # If power was restored before the shutdown kicked in, cancel it.
    
41. pr:12345:powerokwait:/sbin/shutdown -c "Power Restored; Shutdown Cancelled"
    
42. 
    
43. 
    
44. # Run gettys in standard runlevels
    
45. 1:2345:respawn:/sbin/mingetty tty1
    
46. 2:2345:respawn:/sbin/mingetty tty2
    
47. 3:2345:respawn:/sbin/mingetty tty3
    
48. 4:2345:respawn:/sbin/mingetty tty4
    
49. 5:2345:respawn:/sbin/mingetty tty5
    
50. 6:2345:respawn:/sbin/mingetty tty6
    
51. 
    
52. # Run xdm in runlevel 5
    
53. x:5:respawn:/etc/X11/prefdm -nodaemon
    

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想把运行级别改成init 3
修改18行为id:3:initdefault:
不知道如何用命令实现。

在坛子搜索了下，找到一个很有用的帖子，无奈sed正则表达不懂，还请大侠指点。

http://bbs.chinaunix.net/forum.php?mod=viewthread&tid=4082591

关阴月飞

回复 1# o8xv0123


    用得着那么复杂么，直接替换就好：

1. sed -i 's/id:5:initdefault:/id:3:initdefault:/' initab

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elu_ligao

就改那一个地方没必要用sed, 直接进去修改就行

非要用， 你知道是18行   sed -i '18s/5/3' /etc/inittab
          或者你知道是 id:5:initdefault: 这个格式的这行   sed -i '/id:5:initdefault:/s/5/3/p' /etc/inittab

o8xv0123

回复 3# elu_ligao


谢谢你的方法，我自己也找到了一个方法，找id: 打头的那行

1. sed 's/^id:.*$/id:3:initdefault:/' /etc/inittab

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o8xv0123

回复 2# 关阴月飞


    呵呵 ， 谢谢 ， 好方法