improve tip, no root, round up memsize

issues/issue-10/50_TIPS.html

@@ -2,14 +2,20 @@
 <div class="puffies" aria-hidden="true">🐡🐡🐡</div>
 <h2>Shell tips</h2>
 <p>
-To improve performances or avoid disk i/o, one may mount /tmp in memory (mfs). As example to create a /tmp using 10% of available RAM:
+To improve performances or avoid disk i/o, one may mount /tmp in memory (mfs). The new fstab entry would look like this : 
+</p>
+<pre> swap /tmp mfs rw,nodev,nosuid,-s=800MB 0 0</pre>
+Of course, replace the size 800MB according to how much memory you want to let for /tmp.
+</p>
+<p> To know how much memory you have, you may use dmesg and awk : </p>
+<pre>dmesg | awk '/avail mem/'</pre>
+<p>
+As example to create a /tmp using 10% of available RAM, the following command will output the line to copy in /etc/fstab to replace "/tmp" entry, using awk to compute the size :
 </p>
 <pre>
-# sed -i '/\/tmp /s/^/\#/' /etc/fstab
-# printf "swap /tmp mfs rw,nodev,nosuid,-s=%sB 0 0\n" \
-    $(dmesg |awk '/avail mem/ { print $4 /10 }') \
-	>> /etc/fstab
-# chmod 1777 /tmp
-# mount -a
+printf "swap /tmp mfs rw,nodev,nosuid,-s=%sB 0 0\n" \
+    $(dmesg |awk '/avail mem/ { print int($4 /10) }')
 </pre>
+<p>You may have to adjust newly created /tmp permissions:</p>
+<pre> # chmod 1777 /tmp</pre>
 </article>