2010年4月25日 星期日

PUPPY Start process

http://www-128.ibm.com/developerworks/linux/library/l-linuxboot/?ca=dgr-lnxw06LinuxBoot

1. /sbin/init. as configured through /etc/inittab

2 /etc/fstab 的用途

/etc/fstab 是設定分割區與 mount 目錄關係的檔案,開機時會依這個檔案的內容 mount 檔案系統,mount 檔案系統的命令為:

linux# mount -av

會依 /etc/fstab 的內容 mount 進除了 root 以外的所有檔案系統。


init 是在核心 mount 進 root 後,第一個執行的程式 (第一個 process),init 所負責的工作包括:

  • 執 行 /etc/rc.d/rc?.d/ 裡的 scripts
  • 將系統由開機狀態 (boot-up state) 切換至多使用者狀態 (multiuser state)
  • 負責載入 tty (本地端) 的 login shell
  • 負 責開機與關機的程序 (procedure)。
3 /etc/rc.d/rc.sysinit


(1) Puppy doesn't use run levels

(2) X starts with the command 'exec xwin' near the bottom of /etc/profile, it can be removed or commented out.




Useful tools for locating things:
    grep
    which
    readlink


Code:
# grep -nR startx /etc
/etc/ati/authatieventsd.sh:32: # vary depending upon whether X was started via xdm/kdm, gdm or startx, so
/etc/ati/authatieventsd.sh:54: # Finally, check for startx
# which startx
/usr/X11R7/bin/startx
# readlink /usr/X11R7/bin/startx
xwin
# grep -nR xwin /etc
/etc/cups/mime.convs:67:#image/x-xwindowdump application/vnd.cups-postscript66 imagetops
/etc/cups/mime.convs:99:#image/x-xwindowdump application/vnd.cups-raster 100 imagetoraster
/etc/cups/mime.types:111:#image/x-xwindowdump xwd string(4,<00000007>)
/etc/rc.d/rc.country:126: #xwin also set these...
/etc/rc.d/rc.country:130: #...this needs work. messes up font set required by dialog program. see also /usr/X11R7/bin/xwin.
/etc/rc.d/rc.sysinit:388:#note, if wanted to detect serial mouse here, k2.6.25.16 has module 'sermouse' that must be loaded (currently in xwin).
/etc/rc.d/rc.update:98: cp -af $NEWFILESMNTPT/usr/X11R7/bin/xwin /usr/X11R7/bin/
/etc/profile:196: exec xwin
/etc/mime.types:409:image/x-xwindowdump xwd
#

Grep searched through all the files in /etc to find the ones that contained the string 'startx' and returned the filenames, line numbers, and the lines themselves. Looking at them, they didn't seem to run it. So, I used the "which" command to see where the startx command was located. Then the "readlink" command told me that startx was actually a symlink to the xwin script (if it had been a real file, "readlink" wouldn't have returned anything). So then I did another grep to find the files that mention "xwin". Looking through the lines returned, only /etc/profile looks like it runs xwin, on line 196.

I already knew which file it was. But this is roughly the process I would use to find out if I didn't know. I often want to know which script is modifying a configuration file or doing some task. I usually look in /etc first, and if I don't see it there, I try /usr/sbin. When looking in the /usr tree, it can be a good idea to give grep the "-I" flag (that's an uppercase i, not an L) so that it doesn't look at binary files.

Mastering Unix Shell Scripting Notes

1. While studying
with this book we will cover most shell scripting techniques about seven times, each
time from a different angle, solving a different problem. I have found this learning
technique to work extremely well for retention of the material to memory.

2.Unix Special Characters
\ ( ; # $ ? & * ( ) [ ] ` ‘ “ +

2010年4月11日 星期日

Linux works

1. printing mechanism
2. java usb api testing
3. netsetup xwindows start up fix
4. sudden shutdown