Shell script
s="Hello World!" echo $s # Hello World! a=${s,,} echo $a # hello world! b=${s^^} echo $b # HELLO WORLD!
O/p
Add repository
sudo add-apt-repository ppa:webupd8team/java
Update
sudo apt-get update
Install Java
sudo apt-get install oracle-java8-installer
Setting Java environment variables
sudo apt-get install oracle-java8-set-default
chk java version
java -version
Get installation path
which java
Switching between Oracle Java 8 and Java 7
sudo update-java-alternatives -s java-7-oracle
Setting Up JAVA_HOME
Edit /etc/profile (sudo nano /etc/profile ) and add the following
export JAVA_HOME=/usr/lib/jvm/java-8-oracle
save the file and execute
source
/etc/profile
Tasksel installation
First we need to install Tasksel (Tasksel is a Debian/Ubuntu tool that installs multiple related packages as a co-ordinated “task” onto your system. This program is used during the installation process, but users can also use tasksel at any time.)
open teminal (Ctrl+Alt+T) and execute the command
sudo apt-get install tasksel
After installing Tasksel open the tasksel
sudo tasksel
Move the cursor using arrow key and keep cursor near LAMP server and press space button from keyboard for selection, after selecting you can see a star inside the square bracket (press the space again for remove selection )
Press enter key for proceed installation
while installing it will ask for mysql user password and confirm password. Provide password and press enter key to proceed
You are done with the installation,
You can see a www folder created in /var folder.
Open your browser and type http://localhost you can see a default page.
Now you can create your php files inside /var/www/html (Document root) folder, if you kee the folder outside html folder (/var/www) it will not work.
Open default.conf file (located in /etc/apache2/site-available/000-default.conf) with super user permission
sudo gedit /etc/apache2/sites-available/000-default.conf
You can see the DocumentRoot /var/www/html, this you can change to /var/www (you can set any of your folder as document root just give your folder path after DocumentRoot )
Save this file
create a php file outside html folder (/var/www) and add some content
Restart apache and test http://localhost/index.php in your browser
Changing file ownership
$ chown ownername folder/filename $ chown user1 /myfolder $ chown mikky file.txt $ chown -R mikky /myfiles/photos //change the group of file. $ chown :game data.txt //the owner is set to charly followed by a colon and a group ownership is set to game group $ chown charly:game data.txt
Changing group ownership of a file/folder
chgrp [options] group FSO
$ chgrp group_name file_name
Viewing permissions
$ ls -l
Changing permissions
chmod who=permissions filename
eg
$ chmod g=rx filename $ chmod o=rx filename //adding write permission $ chmod g+w filename //removing write permission chmod a-w filename
Copying permissions
$ chmod g=u filename
Numeric method
$ chmod xxx filename $ chmod 755 filename //recursive $ chmod -R 777 foldername
Permission Groups :
Permission Types :
Binary References
Value | Meaning |
777 | (rwxrwxrwx) No restrictions on permissions. Anybody may do anything. Generally not a desirable setting. |
755 | (rwxr-xr-x) The file’s owner may read, write, and execute the file. All others may read and execute the file. This setting is common for programs that are used by all users. |
700 | (rwx——) The file’s owner may read, write, and execute the file. Nobody else has any rights. This setting is useful for programs that only the owner may use and must be kept private from others. |
666 | (rw-rw-rw-) All users may read and write the file. |
644 | (rw-r–r–) The owner may read and write a file, while all others may only read the file. A common setting for data files that everybody may read, but only the owner may change. |
600 | (rw——-) The owner may read and write a file. All others have no rights. A common setting for data files that the owner wants to keep private. |
Take all the update and run update-manager -d from terminal
sudo update-manager -d