May 5th, 9:00AM-5:00PM,Sunday, Room 304, YangBang Shanghai
In the morning,
Introduced the environment of RHCE experiment, also emphasized how necessary it is to join this RHCE training course.
At noon,
Fast food in FamilyMart. After that, a short break.
In the afternoon,
RHCE training started at 1:00PM.
I picked up some points as follows.
1 passwd/useradd
2 run_level
0- halt
1- textmode. Needn't authentication.
2- Textmode.Need authentication. Enable Network service.
3- Textmode. Need authentication. Enable Network service.It’s not able to switch to level 5 without reboot.
4- Reserve
5- Xwindow. Need authentication. Enable Network service.It’s able to switch to level 3 even without reboot.
6- Reboot.
3 How to switch to root
3.1 su root
3.2 su – root
The difference between above two cases. New shell or not.
4 User type
Super user – root, id=0
System user -eg, Apache, Id=[0,500],
Normal user -eg, Allen, id >=500
Notice: By default, it’s enabled to login linux with root or normal user, but disabled to login with system user. Why? Pls refer to /etc/shadow.
5 View user information
Id
Id username
6 Selinux
To be frankly, my daily work is not involved with Selinuxtoo much. Very often,I disable this function to avoid some potentail unknown issues.
7 linux option rule
ls- - all
ls- a
--, following string
-, following char
8 linux command last/history
9 man
man1 Executable programs or shell commands
man2 System calls (functions provided by thekernel)
man3 Library calls (functions within programlibraries)
man4 Special files (usually found in /dev)
man5 File formats and conventions eg /etc/passwd
man6 Games
man7 Miscellaneous (including macro packages and convenâ€tions),e.g. man(7), groff(7)
man8 System administration commands (usually onlyfor root)
man9 Kernel routines [Non standard]
The difference between below two cases
1 man ls
2 man 1 ls
10 How to get information.
For example,linux command grep
1 whatis grep
2 grep - - help
3 man grep
4 info grep
Absolutely, man will be my first choice.