Linux System Administration

useradd

If you do not wish to add new user account to into your Linux system by using a GUI tools, you can do this task from a command line with useradd command.

useradd -mc "user name" -s /bin/bash john

The previous command will create a new user account for user john. -mc options instruct a useradd comment to put a comment about new user which is very often use to specify user's full name. -s option will select path the a default shell.

adduser

Another way to add use is to use adduser command. However this command may not be available on every distribution of Linux. Simply type:

adduser john

and follow instructions to answer some details regarding to a new user account.

This article features some simple examples on how to add or subtract a time from a current date. At first we use a native date sytax to do this trick and later we will see how this can be done manually by converting date to an epoch time. Let's start with a simple backup script based on the date Linux command:

#!/bin/bash

tar cjf linuxconfig_$(date +%H%M-%d%m%Y).tar.bz2 ~/public_html

Every time the script is executed it will create a file with a current date included in the file name. The backup problem is solved. However, we do not usually want to keep all backup files indefinitely or until they consume all available free space. This is where the subtraction arithmetics with Linux date command comes handy. Let's see couple examples how to subtract time from a current date using date string: Subtract 10 years from a current date:

Read more...

It is highly recommended to use the Eclipse IDE as an Android application development environment. Eclipse IDE nicely integrates a Android SDK into Eclipse by the use of Android Development tools. In case that you have decided to use Eclipse IDE here are some shortcut to make your android application development much faster:

Action Keyboard Shortcut
Create a new file in the current package Alt+Shift+N
Organize the import statements Ctrl+Shift+O
Navigate to the source definition F3
Rename an object Alt+Shift+R
Search through Java files Ctrl+H
Open a particular type Ctrl+Shift+T
Find declarations Ctrl+G
Navigate left Alt+left-pointing arrow
Navigate right Alt+left-pointing arrow



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