title: Invoking 'date' command inside awk string, with +%a formatting
body: <p>Still newish to the site, but here goes...
  Basically I'm storing events in multiple files, with each event being a line and each line containing dates ($1), start($2) and stop($3) times and several other pieces of data. I use two double underscores ("__") as Field Separators. I've been using a variety of shell scripts to manage the data, and I was using awk to calculate stats and I'm having trouble invoking the date function so I can get a total by day of the week. After much tinkering and scanning of discussion boards I got to this:</p>
  
  <pre><code>ls /home/specified/folder/MBRS.db/* |
  xargs -n 1 -I % awk -F"__" '$6 == "CLOSED" &amp;&amp; $1 &gt;= "'$backDATE'" { print $0 }' % |
  awk 'BEGIN{FS="__"}{specDATE=system("date --date="$1" +%a")} specDATE == "Tue" {print $2" "$3}'
  </code></pre>
  
  <p>or</p>
  
  <pre><code>ls /home/lingotech/Einstein/data/MBRS.db/* |
  xargs -n 1 -I % awk -F"__" '$6 == "CLOSED" &amp;&amp; $1 &gt;= "'$backDATE'" { print $0 }' % |
  awk 'BEGIN{FS="__"}system("date --date="$1" +%a") == "Mon" {print $2" "$3}'`
  </code></pre>
  
  <p>Instead of outputting the start and stop times, I'm getting a list of all the different days of the week for each entry.</p>
  
  <p>I've tried more variations of the date usage than I care to admit, including:</p>
  
  <pre><code>for y in Sun Mon Tue Wed Thu Fri Sat; do
    for directory in $( ls /home/specified/directory/MBRS.db/* | xargs -n 1 ); do
      printf "."
      [[ $( cat $directory | awk -F"__" '$6 == "CLOSED" &amp;&amp; $1 &gt;= "'$backDATE'" { print $1 }' | xargs -n 1 -I z date +%a -d z ) == "$y" ]] &amp;&amp; echo BLAH
    done
  done
  </code></pre>
  
  <p>Some helpful explanation of what I'm screwing up would be much appreciated. Thanks in advance. Oh and I'm storing the date in YYMMDD format but that doesn't seem to be an issue for ubuntu server's version of 'date'.</p>