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Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

List all installed kernels on Ubuntu except current one
Lists all installed kernels minus the current one. This is useful to uninstall older kernels that take too much space on /boot partition.

generate random identicon

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Capitalize the first letter of every word

share internet connection with only one network interface
the below command create a alias for share your internet connection with another. $ifconfig eth0:1 192.168.0.1/24 Its obviously necessary too activate the iptables post-routing and ip forwarding, as root: $modprobe iptable_nat $iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE $echo 1 > /proc/sys/net/ipv4/ip_forward Be sure that the alias 192.168.0.0/24 is not your active real ip range

Check the hard disk vendor and model on Apple Mac

Convert seconds to [DD:][HH:]MM:SS
Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

Delete line number 10 from file
Very useful when the ssh key of a host has changed and ssh refuses to connect to the machine, while giving you the line number that has changed in ~/.ssh/known_hosts.

Find broken symlinks
To understand why this is the equivalent of "find -L /path/to/search -type l, see http://ynform.org/w/Pub/FindBrokenSymbolicLinks or look at http://www.gnu.org/software/findutils/manual/html_mono/find.html


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