Nov 6, 2008

Handy Nix Shell Commands - Alarm Clock Oneliners and More

Some linux commands are fantastic!

I found some nice ones in a slashdot postings about surprising linux commands and others come from slashdot user tpwch.

Alarm Clocks and Notices

Want a simple alarm clock? Try this one:
echo "cat /dev/urandom > /dev/dsp" | at 7am tomorrow

Your food is in the oven?
sleep $((20*60)); xmessage "Dinner is done"

You can also use zenity to get a popup message:
sleep $((20*60)); zenity --info --text "Dinner is done"

Or, if you prefer a voice message, you can use espeak or festival, which I explain in Free Text-to-Speech.
sleep $((20*60)); echo "Take the food out of the oven" | espeak

Notification of events.

For example, notifying me when some specific thing changed on a website:
CHECKLINE="$(curl -s http://somewebsite.org/somepage.html [somewebsite.org] | grep "currently undergoing maintenence")"
while true; do
sleep 120
[ -z "$CHECKLINE" ] && xmessage "somewebsite is open again" && exit
done

Checking for changes on a website:
while true; do
OLD_MD5=${MD5}
CONTENT=$(elinks -dump 1 -dump-charset iso-8859-1 "http://someurl.com/track?id=someid")
MD5=$(echo -n $CONTENT | md5sum -)

[ "${MD5}" != "${OLD_MD5}" ] && {
xmessage "$(printf "New action: :\n\n${CONTENT}")"
}
sleep 120
done

Prank Greetings

Some nice greetings to your colleague?
cat /dev/random | write colleague

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