How to Install Java 8 on Debian GNU/Linux 9 (Stretch)

In this article, I will go through the process of installation of Java 8 on Debian 9 Stretch. Java comes in two flavors and we install both. OpenJDK is open source version that is compatible with most software.  And Oracle JavaSE is the proprietary version that should be used if your java application is incompatible with OpenJDK. There is also a neat mechanism for switching default Java in case you have both of them installed. In one of our earlier article we have explained java installation on rpm based system and this time we will have on Debian.

Installing OpenJDK

We will start from installing the OpenJDK. There are two packages that we can install, a JRE and JDK. Those familiar with Java already know what this means, but for other lets mention what it means.  JRE means Java Runtime Environment and JDK means Java Development Kit. So the first one is used if you are going only to start Java program, while JDK packs a javac compiler. Meaning if you are developer, you need JDK, otherwise JRE is ok.

To install JRE use this command after getting root access with su:

apt-get install default-jre

Depending on what kind of Debian install you did (CD, DVD, USB drive), this might or might not be already installed. On the other hand, JDK is most probably not installed. To install it, type:

apt-get install default-jdk

And you are set to go.

Installing Oracle Java

To install Oracle java we can use Webupd repository that is made for Ubuntu, but it also works for Debian. To add repository you first need to add add-apt-repository command if it is not installed (and that depends upon install options you selected).

apt-get install software-properties-common dirmngr

After installing this, we can add repository

add-apt-repository "deb http://ppa.launchpad.net/webupd8team/java/ubuntu yakkety main"

Repository is still not ready to use, we need to add key, we will see what key is missing after we run update command

apt update

Next we add key:

apt-key adv --keyserver keyserver.ubuntu.com --recv-keys C2518248EEA14886

And now we can install Oracle Java 8

apt-get install oracle-java8-installer

This will start install process, it will download newest Java 8 from Oracle site and install it. You will also get prompted by ncurses environment to accept the Oracle EULA for Java.

After it is done, you can run following command to see which exact version you have installed

java -version

Should get output similar to this

java version "1.8.0_131"
Java(TM) SE Runtime Environment (build 1.8.0_131-b11)
Java HotSpot(TM) 64-Bit Server VM (build 25.131-b11, mixed mode)

If we need Java 9 (development version as of time of writing) or Java 7 or 6 (legacy versions), we can install those as well. We need to re-run above command, except we will change number 8 for 6, 7 or 9.

Managing which Java will be using by default

Of you installed Oracle Java 6, 7, 8 and 9, plus OpenJDK, then you have 5 java installations. If you are developing for the legacy environment, you would want to set your system to use only one Java version, and to do that you dont need to remove all other java versions. Instead, you need to use following command:

update-alternatives --config java

It will give you output similar to this

Here you only need to enter the number that is shown before Java entry that you want to use as default. The asterisk signifies which one is used currently. After you changed the java alternative, the java -version command should give you different output.

You could also select default java compiler with following command

update-alternatives --config javac

Any other tool like javaws can be also set simply by changing last word in this command to appropriate tool name.

Setting the Environment Variable

If you are using some Java Application server like JBoss or Tomcat, then you will need $JAVA_HOME variable set. To set it use above update-alternatives --config java command to see where java is installed.

Then edit following file in nano

nano /etc/environment

If you just installed Java, file is empty, so add some line like this

JAVA_HOME="/usr/lib/jvm/java-8-openjdk-amd64"

That is if you want OpenJDK to be your $JAVA_HOME.

Save file and run source command to load new variable

source /etc/environment

Now check if it works

echo $JAVA_HOME

it should give you output like this to this

/usr/lib/jvm/java-8-openjdk-amd64

That means that environment variable has been successfully set.

Conclusion

We have successfully installed OpenJDK and Oracle Java SE and now have the environment set up so you can on top of it install some Java EE application servers like Red Hat JBoss, Oracle WebLogic, WildFly or Apache Tomcat. On top of that you can develop and deploy your application. Or you simply want to have plain Java SE desktop applications on your Debian 9 desktop. Either way,  now you can do it.

Autor: https://linoxide.com/debian/install-java-8-debian-gnulinux-9-stretch/ 

Cor Color Bash Prompt Debian

Green Prompt for your user

Edit ”~/.bashrc” and change:

#force_color_prompt=yes

to:

force_color_prompt=yes

To change it for all new users make the same in ”/etc/skel/.bashrc”.

Red Prompt for root

Edit ”/root/.bashrc” and change ”force_color_prompt=yes” like for your user.

Now change the color to red. Search this line:

PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '

and change it to:

PS1='${debian_chroot:+($debian_chroot)}\[\033[01;31m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '

Note: For this change to take effect, you must log out then log in again.

Debian (older versions)

Green Prompt for your user

Open ”~/.bashrc” and append:

PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '

Red Prompt for root

Edit ”/root/.bashrc” and append:

PS1='${debian_chroot:+($debian_chroot)}\[\033[01;31m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]$ '

Other colors

Color Code
Black 30
Red 31
Green 32
Brown 33
Blue 34
Purple 35
Cyan 36
Light Gray 37 

Here are the rest of the colour equivalences:

Black       0;30     Dark Gray     1;30
Blue        0;34     Light Blue    1;34
Green       0;32     Light Green   1;32
Cyan        0;36     Light Cyan    1;36
Red         0;31     Light Red     1;31
Purple      0;35     Light Purple  1;35
Brown       0;33     Yellow        1;33
Light Gray  0;37     White         1;37

Script PHP para forçar download de arquivos TXT e OPVN

Os navegadores de internet atualmente estão cheios de recursos, sçao capases de executar arquivos em diversos formatos como imagens, vídeos, músicas arquivos de texto como PDF, e diversos outros arquivos, porém ocorre que por necessidade do desenvolvedor e para facilitar a vida do usuário as veses precisamos que o arquivo seja baixado para o computador do usuário e não aberto no navagador, pois muitos usuários não saberam salvar um arquivo aberto no navegador, abaixo apresentarei um método de resolver esse problema.

Em um arquivo download.php coloque o seguinte conteúdo:

   $arquivo = $_GET["arquivo"];
   if(isset($arquivo) && file_exists($arquivo)){ //testa se o arquivo e a variavel não esta vazia e se o arquivo realmente existe
      switch(strtolower(substr(strrchr(basename($arquivo),"."),1))){ // verifica a extensão do arquivo para pegar o tipo
         case "pdf": $tipo="application/pdf"; break;
         case "exe": $tipo="application/octet-stream"; break;
         case "zip": $tipo="application/zip"; break;
         case "doc": $tipo="application/msword"; break;
         case "xls": $tipo="application/vnd.ms-excel"; break;
         case "ppt": $tipo="application/vnd.ms-powerpoint"; break;
         case "gif": $tipo="image/gif"; break;
         case "png": $tipo="image/png"; break;
         case "jpg": $tipo="image/jpg"; break;
         case "mp3": $tipo="audio/mpeg"; break;

         case "txt": $tipo="text/plain"; break;

         case "ovpn": $tipo="text/plain"; break;                  case "php": // deixar vazio por seurança
         case "htm": // deixar vazio por seurança
         case "html": // deixar vazio por seurança
      }
      header("Content-Type: ".$tipo); // informa o tipo do arquivo ao navegador
      header("Content-Length: ".filesize($arquivo)); // informa o tamanho do arquivo ao navegador
      header("Content-Disposition: attachment; filename=".basename($arquivo)); // informa ao navegador que é tipo anexo e faz abrir a janela de download, tambem informa o nome do arquivo
      readfile($arquivo); // lê o arquivo
      exit; // aborta pós-ações
   }
?>

Como é possível ver acima um case ficar resposável por definir o tipo do arquivo à partir da extensão, caso você queira adicionar mais tipos, é só adicionar mais um case com a extensão e o tipo do arquivo.

Depois faça um arquivo com o nome index.html e coloque nele o seguinte conteúdo.



Baixar Arquivo

No código acima passamos como um parâmetro via GET o diretório do arquivo que se deseja baixar.
Como foi dito se você quiser adicionar mais algum case segue abaixo uma lista te extensões e tipos que são chamados de Mime types.

ai     application/postscript
aif     audio/x-aiff
aifc     audio/x-aiff
aiff     audio/x-aiff
asc     text/plain
atom     application/atom+xml
au     audio/basic
avi     video/x-msvideo
bcpio     application/x-bcpio
bin     application/octet-stream
bmp     image/bmp
cdf     application/x-netcdf
cgm     image/cgm
class     application/octet-stream
cpio     application/x-cpio
cpt     application/mac-compactpro
csh     application/x-csh
css     text/css
dcr     application/x-director
dif     video/x-dv
dir     application/x-director
djv     image/vnd.djvu
djvu     image/vnd.djvu
dll     application/octet-stream
dmg     application/octet-stream
dms     application/octet-stream
doc     application/msword
dtd     application/xml-dtd
dv     video/x-dv
dvi     application/x-dvi
dxr     application/x-director
eps     application/postscript
etx     text/x-setext
exe     application/octet-stream
ez     application/andrew-inset
gif     image/gif
gram     application/srgs
grxml     application/srgs+xml
gtar     application/x-gtar
hdf     application/x-hdf
hqx     application/mac-binhex40
htm     text/html
html     text/html
ice     x-conference/x-cooltalk
ico     image/x-icon
ics     text/calendar
ief     image/ief
ifb     text/calendar
iges     model/iges
igs     model/iges
jnlp     application/x-java-jnlp-file
jp2     image/jp2
jpe     image/jpeg
jpeg     image/jpeg
jpg     image/jpeg
js     application/x-javascript
kar     audio/midi
latex     application/x-latex
lha     application/octet-stream
lzh     application/octet-stream
m3u     audio/x-mpegurl
m4a     audio/mp4a-latm
m4b     audio/mp4a-latm
m4p     audio/mp4a-latm
m4u     video/vnd.mpegurl
m4v     video/x-m4v
mac     image/x-macpaint
man     application/x-troff-man
mathml     application/mathml+xml
me     application/x-troff-me
mesh     model/mesh
mid     audio/midi
midi     audio/midi
mif     application/vnd.mif
mov     video/quicktime
movie     video/x-sgi-movie
mp2     audio/mpeg
mp3     audio/mpeg
mp4     video/mp4
mpe     video/mpeg
mpeg     video/mpeg
mpg     video/mpeg
mpga     audio/mpeg
ms     application/x-troff-ms
msh     model/mesh
mxu     video/vnd.mpegurl
nc     application/x-netcdf
oda     application/oda
ogg     application/ogg
pbm     image/x-portable-bitmap
pct     image/pict
pdb     chemical/x-pdb
pdf     application/pdf
pgm     image/x-portable-graymap
pgn     application/x-chess-pgn
pic     image/pict
pict     image/pict
png     image/png
pnm     image/x-portable-anymap
pnt     image/x-macpaint
pntg     image/x-macpaint
ppm     image/x-portable-pixmap
ppt     application/vnd.ms-powerpoint
ps     application/postscript
qt     video/quicktime
qti     image/x-quicktime
qtif     image/x-quicktime
ra     audio/x-pn-realaudio
ram     audio/x-pn-realaudio
ras     image/x-cmu-raster
rdf     application/rdf+xml
rgb     image/x-rgb
rm     application/vnd.rn-realmedia
roff     application/x-troff
rtf     text/rtf
rtx     text/richtext
sgm     text/sgml
sgml     text/sgml
sh     application/x-sh
shar     application/x-shar
silo     model/mesh
sit     application/x-stuffit
skd     application/x-koan
skm     application/x-koan
skp     application/x-koan
skt     application/x-koan
smi     application/smil
smil     application/smil
snd     audio/basic
so     application/octet-stream
spl     application/x-futuresplash
src     application/x-wais-source
sv4cpio     application/x-sv4cpio
sv4crc     application/x-sv4crc
svg     image/svg+xml
swf     application/x-shockwave-flash
t     application/x-troff
tar     application/x-tar
tcl     application/x-tcl
tex     application/x-tex
texi     application/x-texinfo
texinfo     application/x-texinfo
tif     image/tiff
tiff     image/tiff
tr     application/x-troff
tsv     text/tab-separated-values
txt     text/plain
ustar     application/x-ustar
vcd     application/x-cdlink
vrml     model/vrml
vxml     application/voicexml+xml
wav     audio/x-wav
wbmp     image/vnd.wap.wbmp
wbmxl     application/vnd.wap.wbxml
wml     text/vnd.wap.wml
wmlc     application/vnd.wap.wmlc
wmls     text/vnd.wap.wmlscript
wmlsc     application/vnd.wap.wmlscriptc
wrl     model/vrml
xbm     image/x-xbitmap
xht     application/xhtml+xml
xhtml     application/xhtml+xml
xls     application/vnd.ms-excel
xml     application/xml
xpm     image/x-xpixmap
xsl     application/xml
xslt     application/xslt+xml
xul     application/vnd.mozilla.xul+xml
xwd     image/x-xwindowdump
xyz     chemical/x-xyz
zip     application/zip

Autor: http://gratissimpiratanao.blogspot.com.br/2014/03/script-php-para-forcar-download-de.html