UNIX/Linux/Ubuntu system administration DAY 02

Linux system commands

1. lastb : show details of failed logins
2. last : display the last login and logout details of all users
3. uptime: display how long the system has been running
4. who: list of users who are currently logged in to the system
5. w: display information about users currently logged in to the system
6. telinit: change run levels (e.g. single user mode: run level 1)
7. netstat -rn: check the default gateway on an unix/linux machine

Useful Linux commands

1. apropos: search for strings that exist in each Linux command e.g. apropos printing
2. cat /etc/shells: list all available shells in the system
3. set: display all environmental settings

Managing users and groups

1. /etc/passwd
2. /etc/groups: consists of a list of groups each in a different line

Managing partitions

1. fdisk: mange partition table
2. sfdisk: manage partition table
3. parted: a partition manipulation program
4. partprobe: inform the OS of partition table changes

Manage packages using RPM

1. rpm -i packagename: install a package
2. rpm -F packagename: reinstall a package
3. rpm -U packagename: upgrade a package
4. rpm -e package name: remove a package
5. rpm -qa list all packages that are installed on your system

YUM component acts as the front-end package installer for RPM

1. yum install R R-core R-core-devel R-devel //to install R in Linux/Centos

Web systems day 06-Topic: declaration

Common <!DOCTYPE> declaration

References

1. http://www.w3schools.com/ accessed date 31 July 2012

IT for Users in Organisations Day 01

Ways to increase productivity

1. higher production
2. improve quality
3. improve efficiency
4. improve effectiveness
5. automate manual tasks
6. empowering staff

Ways to improve customer service

1. increase customer satisfaction
2. extend customer services
3. monitor customer contacts – feedback and analysis
4. customer service online
5. automate manual tasks
6. empowering staff

References

1. Melbourne Institute of Technology (Semester 2, 2012). BN105 IT for Users in Organisations Lecture Notes.

UNIX/Linux/Ubuntu system administration DAY 01

Force new users change their password at their first log-in

1. top command shows more details than ps command. It is like running ps permanently while allowing users to change parameters or apply filters to the output.
2. sar command shows the system's activities in a period of time (e.g. "> sar 10 5" get 5 samples in a 10-second interval.).
3. "user@linuxhost:> find . > list_of_files.txt" creates a list of files and save it into list_of_files.txt.
4. "user@linuxhost:> find  /user/local -xdev > list_of_files_in_local_folder.txt" creates a list of files in the folder /user/local and save it ist_of_files_in_local_folder.txt.
5. "user@linuxhost:> grep passwd list_of_files.txt" search the location of the file passwd.
6. "user@linuxhost:> ps uawx | head" shows the 10 processes using most of the CPU cycles.
7. "user@linuxhost:> man -s 4 passwd" access information contained in section 4 of the command passwd.
8. Create a new user (useradd), create the password for the user (passwd username) make sure the user's home directory exists and corresponds to the entry in the /etc/passwd file, verify that the user owns his or her home directory and startup files, and that they are readable (and, in the case of the home directory, executable). E.g. chown -R username /home/username; chgrp -R username /home/username.
9. "user@linuxhost:> id username" to display user/group information.
10. "user@linuxhost:> usermod -G admin -a username" add username to group admin.
11. "root@linuxhost:> shutdown -P now" to shutdown the machine right away.
12. Modify /etc/sudoers file in order to use command sudo. E.g. EDITOR="emacs" visudo; and use the usermod command at list number 10 above.

References

Erik M. Keller, Unix/Linux Survival Guide, Charles River Media, Inc. , 2006.

CSS Day 01

CSS Box model

CSS ID selector example

CSS Class selector example

CSS Syntax 

CSS Pseudo class example

CSS Pseudo element example

References

1. http://www.w3schools.com/ accessed date 18 July 2012