title: bash shell $HOME assignment and script execution
body: <p>I've just begun learning Unix and have so far encountered two elementary though difficult to resolve problems:</p>
  
  <ul>
  <li>When I set <code>HOME=''</code> in a shell script to a designated directory, the <em>current</em> directory no longer seems to be recognized. That is, 'cd ~/' spits out the message: 'no such file or directory' message. Although, curiously enough, if aliases assignments are made within the script, a source call seems to activated them nonetheless. How come?</li>
  </ul>
  
  <p>Ex: </p>
  
  <pre><code>$ more .profile
  HOME="~/Documents/Basics/Unix/Unix_and_Perl_course"
  cd $HOME
  [...]
  $ source .profile
  -bash: cd: ~/Documents/Basics/Unix/Unix_and_Perl_course: No such file or directory
  </code></pre>
  
  <ul>
  <li>When I created a simple shell script via nano ('hello.sh'), I can't seem to execute it simply by typing 'hello.sh' in the terminal. This issue fails to resolve even after I 'chmod +x' the file. What's the problem?</li>
  </ul>
  
  <p>Ex: </p>
  
  <pre><code>$ more hello.sh 
  # my first Unix shell script
  echo "Hello World"
  $ hello.sh
  bash: hello.sh: command not found
  </code></pre>
  
  <p>Thanks!</p>