Commands by DaveQB (9)

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Both view and pipe the file without saving to disk
This is a cool trick to view the contents of the file on /dev/pts/0 (or whatever terminal you're using), and also send the contents of that file to another program by way of an unnamed pipe. All the while, you've not bothered saving any extra data to disk, like you might be tempted to do with sed or grep to filter output.

Generate a Change Log with git
Generate a changelog between the v1 and v2 tags

Quick network status of machine
credit to tumblr engineering blog @ http://engineering.tumblr.com/

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"

Monitor a file's size

Check a server is up. If it isn't mail me.
For some reason the 2&>1 does not work for me, but the shorter stdout/stderr redirection >& works perfectly (Ubuntu 10.04).

Print line immediately before a matching regex.
Use this if you don't have access to GNU grep's -B option.

Update a namecheap @ A record to point to your current internet-facing IP address
Sets the @ A record for your domain hosted by namecheap to your current internet-facing IP address, logs success or failure with syslog, and logs the data returned to /root/dnsupdate. Change the XXX's as appropriate. More info at: http://www.namecheap.com/support/knowledgebase/article.aspx/29/

Create several copies of a file
Copy a file to a range of other files.

Waste time for about 3 minutes
If you're a slow reader and/or you like to ponder, adjust the sleep time to be longer


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