alternatives --config java bash script

You can run the alternatives command non-interactively too. Instead of --config, use the --set option to specify the path of the alternative directly.

sudo alternatives --set java /location/of/jdk1.6/bin/java

Generally, you can feed any program that expects something on the standard input like this:

echo -e "line 1\nline 2\nline 3" | program

I did it using this script:

tmp=`mktemp`
echo 2 > $tmp
alternatives --config java < $tmp
rm -f $tmp

The < means that the content of the $tmp file will be passed to the input of the alternatives command.

Edit: You could simply use a single pipe as other suggested:

echo 2 | sudo alternatives --config java

This worked for me with Java 8:

 alternatives --install /usr/bin/java java /usr/lib/jvm/jre1.8.0_60/bin/java 3
 alternatives --config java <<< '3'