Make tcpdump, wall and useradd match formatting.

pages/common/tcpdump.md

@@ -24,6 +24,5 @@
 
 - capture all traffic except traffic over port 22 and save to a dump file with today's date
 
-```
-tcpdump -w dumpfile.`date +%Y.%m.%d-%H.%M`.pcap not port 22
-```
+`tcpdump -w dumpfile.`date +%Y.%m.%d-%H.%M`.pcap not port 22`
+

pages/common/useradd.md

@@ -4,16 +4,17 @@
 
 - Create new user
 
- `useradd {{name}}`
+`useradd {{name}}`
 
 - Create new user with a default home directory
 
- `useradd -m {{name}}`
+`useradd -m {{name}}`
 
 - Create new user with specified shell
 
- `useradd -s {{/path/to/shell}} {{name}}`
+`useradd -s {{/path/to/shell}} {{name}}`
 
 - Create new user with supplementary groups (mind the lack of whitespace)
 
- `useradd -G {{group1,group2}} {{name}}`
+`useradd -G {{group1,group2}} {{name}}`
+

pages/linux/wall.md

@@ -4,10 +4,14 @@
 > only available to super-user
 
 - send a message
+
 `echo "{{message}}" | wall`
 
 - send a message from a file
+
 `wall {{file}}`
 
 - send a message with timeout (default 300)
+
 `wall -t {{seconds}} {{file}}`
+