Why I can't change directories using “cd”?

Question

I\'m trying to write a small script to change the current directory to my project directory:

#!/bin/bash
cd /home/tree/projects/java

I save

Answer 1

You can combine an alias and a script,

alias proj="cd \`/usr/bin/proj !*\`"

provided that the script echos the destination path. Note that those are backticks surrounding the script name. 

For example, your script could be

#!/bin/bash
echo /home/askgelal/projects/java/$1

The advantage with this technique is that the script could take any number of command line parameters and emit different destinations calculated by possibly complex logic.