Commands using head (314)

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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"

Command to rename multiple file in one go

Run a program transparently, but print a stack trace if it fails
For automated unit tests I wanted my program to run normally, but if it crashed, to add a stack trace to the output log. I came up with this command so I wouldn't have to mess around with core files. The one downside is that it does smoosh your program's stderr and stdout together.

Another way to calculate sum size of all files matching a pattern
Here the pattern is '*.jar', you could pass in any pattern. Another, maybe nicer way to do this is http://www.commandlinefu.com/commands/view/1921/summarise-the-size-of-all-files-matching-a-simple-regex You could replace sed with tr

grep for minus (-) sign
Use flag "--" to stop switch parsing

Change user within ssh session retaining the current MIT cookie for X-forwarding
When you remotely log in like "ssh -X userA:host" and become a different user with "su UserB", X-forwarding will not work anymore since /home/UserB/.Xauthority does not exist. This will use UserA's information stored in .Xauthority for UserB to enable X-forwarding. Watch http://prefetch.net/blog/index.php/2008/04/05/respect-my-xauthority/ for details.

See system users

Delete Mailer-Daemon messages

display the hover text of the most recent xkcd
I look at xkcd in my news reader, but it displays the image's title attribute only for a few seconds which makes reading the longer ones more challenging. So I use this to display it in my console.

Url Encode


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