s.cgi shell blog script

#!/bin/sh

BLOGTITLE="test blog"
BLOGSUBTITLE="super cool!!!"
POSTSDIR="posts"
DEFTAG="uncategorized"

getparam() {
    # Thanks to the site below for this bit of sed:
    #   http://foxlx.acmesystems.it/?id=165
    echo $QUERY_STRING | sed -n "s/^.*$1=\([^&]*\).*$/\1/p" | sed 's/%20/ /g'
}

getposts() {
    ls -t $(find -iname '*.md' | sed 's,^\./,,')
}

posttitle() {
    echo $1 | sed -n 's/^\([^-]*\).*\.md$/\1/p'
}

posttags() {
    TAGS=$(echo $1 | sed -n 's/^[^-]*-\(.*\)\.md$/\1/p' | sed 's/-/ /g')
    [ -z "$TAGS" ] && TAGS="$DEFTAG" # Apply default tag to untagged posts
    echo $TAGS
}

recentposts() {
    POSTS=$(getposts | head -$1)

    for p in $POSTS; do
        TITLE=$(posttitle $p)

        cat << POSTLINK
<a href="s.cgi?post=$TITLE">$(echo $TITLE | sed 's/_/ /g')</a>
<br>
POSTLINK
    done
}

gettags() {
    POSTS=$(getposts)
    TAGS="$DEFTAG"

    for p in $POSTS; do
        for t in $(posttags $p); do
                [ -z "$(echo $TAGS | grep $t)" ] && TAGS="$TAGS $t"
        done
    done

    echo $TAGS
}

taglinks() {
    for t in $*; do
        echo "<a href=\"s.cgi?tag=$t\">$t</a>"
    done
}

showpost() {
    TITLE=$(posttitle $1)
    TAGS=$(posttags $1)

   cat << BLOGPOST
<h3 style="display: inline; float: left; margin: 0;">
$(echo $TITLE | sed 's/_/ /g')
</h3>
<p style="display: inline; float: right; font-size: 80%; margin: 0;">
$(taglinks $TAGS)
</p>
<div style="clear: both;">
<!-- markdown output begins... -->
$(../md2html.awk $1)
<!-- ...and ends -->
</div>
BLOGPOST
}

showtag() {
    echo "<h3>Posts tagged \"$TAGNAME\"</h3>"

    for p in $(getposts); do
        if [ -n "$(posttags $p | grep $TAGNAME)" ]; then
                TITLE=$(posttitle $p)
                cat << POSTLINK
<a href="s.cgi?post=$TITLE">$(echo $TITLE | sed 's/_/ /g')</a>
<br>
POSTLINK
        fi
    done
}


echo "Content-type: text/html"
echo

# Nobody wants to see an empty blog...
if [ -z "$POSTSDIR" ] || [ ! -d $POSTSDIR ]; then
        echo "Nothing to see here!"
        exit 1
fi

cd $POSTSDIR

cat << HEADER
<!DOCTYPE html>
<html>
<head>
<title>$BLOGTITLE</title>
<meta charset="utf-8">
<!-- link to user-defined stylesheet will go here -->
</head>
<body>
<h1 style="margin-bottom: 0;">
<a href="s.cgi" style="color: #000; text-decoration: none;">$BLOGTITLE</a>
</h1>
<p style="margin: 0; font-style: italic;">$BLOGSUBTITLE</p>
<hr>
<div style="display: inline; float: left; width: 65%">
HEADER

POSTNAME=$(getparam post)
TAGNAME=$(getparam tag)

if [ -n "$POSTNAME" ]; then
        P=$(ls $POSTNAME*.md)

        if [ -n "$P" ]; then
                showpost $P
        else
                echo "Post ($POSTNAME) doesn't exist"
        fi
elif [ -n "$TAGNAME" ]; then
        showtag $TAGNAME
else
        showpost $(ls -t *.md | head -1)
fi

cat << FOOTER
</div>
<div style="display: inline; float: right; width: 33%;">
<h4>Recent posts</h4>
<p>$(recentposts 10)<p>
<hr>
<h4>Tags</h4>
<p>$(taglinks $(gettags))</p>
</div>
<div style="clear: both; text-align: center;">
<hr>
<p>Pretty footer text goes here</p>
</div>
</body>
</html>
FOOTER