See all open ports
lsof -i TCP| fgrep LISTEN
Remove top navbar from wordpress
Edit wp-includes/functions.php and add the following add_action(‘after_setup_theme’, ‘remove_admin_bar’); function remove_admin_bar() { if (!current_user_can(‘administrator’) && !is_admin()) { show_admin_bar(false); } } Now the top navbar will only showup for admin users.
Find the largest file in a directory tree
find /path -type f -exec ls -s {} \; | sort -n | tail -1
Compress the contents current directory, but compress the smallest files first
ls -s | awk NR!=1 | sort -n | awk ‘{print $2}’ | xargs bzip2 -9v
Using netstat
netstat -ntulp displays everything that is listening tcp and udp and the ip that it is listening on
View network traffic (by port number)
To view web traffic (for example) use tcpdump -s 0 -w – port 80 | tcpdump -r – -A
Filter duplicate lines from a sorted files
cat list-1 list-2 list-3 | sort | uniq > final.list