title: bash date last with week number
body: <p>To get the date of the last sunday one could use <code>date --date="last sun"</code> for Linux and <code>date -j -v-sun</code> for BSD.</p>
  
  <p>How is it done however if I do have week numbers (1 to 7) instead of strings? I could always use a case-statement to convert the numbers to strings, but I bet there is a better solution for this?!</p>
  
  <p>Thanks for your help.</p>