--- a/s4-blog.sh	Wed Sep 22 08:39:36 2021 +0900
+++ b/s4-blog.sh	Mon Oct 25 18:39:44 2021 +0900
@@ -183,6 +183,7 @@
   blog_notify=`getvalbyid blog notify "$rowid"`
   blog_team=`blog_getteam "$rowid"`
   blog_mode=`getvalbyid blog mode "$rowid"`
+  blog_math=`getvalbyid blog mathjax "$rowid"`
   case "$blog_notify" in # "all", "admin" or "no" (or NULL)
     admin)	notifyto=adm ;;
     *)		notifyto="" ;;
@@ -269,7 +270,7 @@
 	;;
     esac
   fi
-  href4="<a href=\"#bottom\" accesskey=\"b\" title=\"Shortcut: B${nl}to the Bottom\"> 末尾へ</a>"
+  href4="${blog_math:+Math} <a href=\"#bottom\" accesskey=\"b\" title=\"Shortcut: B${nl}to the Bottom\"> 末尾へ</a>"
   $isgrpadmin &&
       href5="<a href=\"?blogseen+$rowid\" accesskey=\"s\" title=\"Shortcut: S${nl}State of Accesses\"> 読刻</a>"
   quizmodefile=$tmpd/quiz; rm -f "$quizmodefile"	# XXX: Global state
@@ -416,6 +417,7 @@
     echo "時間をおいてください(Visit later please)." | html p
     return
   fi
+  echo "${blog_math:+$mathjax}"
   echo '<table class="blog_replies"> <!-- blog:blog_showentry() main table -->'
   # If, nLimit = 50
   # show article:1, hide(2, 3), show(4, ...)
@@ -447,7 +449,7 @@
   err "blog_showentry  Started: `gdate +%S.%03N` ${fetch_ajax:+ajax}"
   # Start blog_replies table
   $CAT $midfile |
-  while IFS='|' read id edit notify uid author uname icon aid \
+  while IFS='|' read -r id edit notify uid author uname icon aid \
 	   tm reki new hte fa imgids
   do
     if [ -n "$omitline" ]; then
@@ -661,7 +663,7 @@
   owner=`getvalbyid blog owner $1`
   title=`getvalbyid blog title $1`
   ge=`gecos "$owner"`
-  htmlowner=`echo ${ge:-$owner}|htmlescape`
+  htmlowner=`printf '%s' "${ge:-$owner}"|htmlescape`
   fh=$tmpd/formhead
   echo "$time [$title]@$htmlowner" > $fh
   lshandoutsub "$owner" "$@" \
@@ -670,7 +672,7 @@
 	   -D_FORMHEAD_="syscmd(cat $fh)" \
 	   -D_FORM_="syscmd(cat)" -D_DUMPHEAD_= -D_DUMPTABLE_= \
 	   $layout/html.m4.html $layout/form+dump-whead.m4.html
-  gn=`echo $owner|htmlescape`
+  gn=`printf '%s' "$owner"|htmlescape`
   echo "<p><a href=\"?lshandoutall+$1\">グループ $gn すべてのレポート板集計</a></p>"
 }
 gethandoutcsv() {
@@ -756,7 +758,7 @@
     _m4 -D_TITLE_="提出状況" $layout/html.m4.html
     ge=`gecos "$owner"`
     tbls=""
-    grptxt=`echo "${ge:-$owner}"|htmlescape`
+    grptxt=`printf '%s' "${ge:-$owner}"|htmlescape`
     echo "<h1>$grptxt 書き込み状況一覧</h1>"
   fi
   if [ -z "$SQL" ]; then
@@ -766,7 +768,7 @@
       [ $brid = 0 ] && continue
       time=`getvalbyid blog ctime $brid|colrm 11`
       title=`getvalbyid blog title $brid`
-      titleH=`echo "$title"|htmlescape`
+      titleH=`printf '%s' "$title"|htmlescape`
       state=`getvalbyid blog state $brid|htmlescape`
       tt="handout_$brid"
       [ "$state" = "frozen" ] && frozen=" $FROZEN_TAG" || frozen=""
@@ -1053,7 +1055,7 @@
     cat <<-EOF
 	<tr>
 	 <td><a href="?home+$uid">`echo "$hexge"|unhexize|htmlescape`</a></td>
-	 <td>`echo ${u%%@*}|htmlescape`</td>
+	 <td>`printf '%s' "${u%%@*}"|htmlescape`</td>
 	 $td${time:----}</td></tr>
 	EOF
   done
@@ -1180,7 +1182,7 @@
     rowid=$((${kwd#\#} + 0))	# Force to be a number
     kc="ar.rowid = $rowid"
   else
-    for k in `echo "$kwd" | sed "s/'/''/g"`; do		# With wrap quotes
+    for k in `printf '%s' "$kwd" | sed "s/'/''/g"`; do	# With wrap quotes
       ctime=""
       if expr x"$k" : 'x@[><= ]*[1-9][][0-9]*-[][0-9:-]*$' >/dev/null >&2; then
 	# '@<2016-10-10'	-> ctime < '2016-10-10'
@@ -1218,14 +1220,14 @@
 	e=""
 	case "$k" in
 	  *${likeesc}*) e="" ;;		# Giving up char-escaping
-	  *%*|*_*) k=`echo "$k"|sed "s/\([%_]\)/${likeesc}\1/g"`
+	  *%*|*_*) k=`printf '%s' "$k"|sed "s/\([%_]\)/${likeesc}\1/g"`
 	       e=" ESCAPE '$likeesc'" ;;
 	esac
 	kc=$kc${kc:+" AND "}"content LIKE '%$k%'$e"
       fi
     done
   fi
-  kwd=`echo "$kwd"|htmlescape`
+  kwd=`printf '%s' "$kwd"|htmlescape`
   owner=`getpar owner`
   owner=${owner:-$1}
   grid=`getpar grid`
@@ -1359,11 +1361,11 @@
   newval=`getvalbyid blog "$2" "$1"`
   alert="${msg:+, \"alert\": \"$msg\"}"
   json=$(cat <<-EOF
-	{"code": $code, "$2": "`echo "$newval"|sed 's/"/\\\\"/g'`"$alert}
+	{"code": $code, "$2": "`printf '%s' "$newval"|sed 's/"/\\\\"/g'`"$alert}
 	EOF
       )
   err blog_setval: returning JSON: "$json"
-  echo "$json"
+  printf '%s\n' "$json"
   exit
 }
 
@@ -1387,7 +1389,7 @@
   else
     owner=`getpar owner`
   fi
-  htmlowner=`echo $owner|htmlescape`
+  htmlowner=`printf '%s' $owner|htmlescape`
   err blog-add: \$1=$grprowid rowid=$rowid owner=$owner
   if isgroup "$owner"; then
     if [ -z "$grprowid" ]; then
@@ -1481,7 +1483,7 @@
   fi
   title=`getvalbyid blog title $rowid`
   owner=`getvalbyid blog owner $rowid`
-  htmlowner=`echo $owner|htmlescape`
+  htmlowner=`printf '%s' $owner|htmlescape`
   qowner=`sqlquotestr "$owner"`
   if [ -z "$title" ]; then
     echo "日記番号指定が無効です。" | html p