Commands by RyanM (1)

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In place line numbering
Add permanent line numbers to a file without creating a temp file. The rm command deletes file10 while the nl command works on the open file descriptor of file10 which it outputs into a new file again named file10. The new file10 will now be numbered in the same directory with the same file name and content as before, but it will in fact be a new file, using (ls -i) to show its inode number will prove this.

Create black and white image
Use ImageMagick to create a "black and white" copy of an image.

send echo to socket network
Using netcat, usuallly installed on debian/ubuntu. Also to test against a sample server the following two commands may help echo got milk? | netcat -l -p 25 python -c "import SocketServer; SocketServer.BaseRequestHandler.handle = lambda self: self.request.send('got milk?\n'); SocketServer.TCPServer(('0.0.0.0', 25), SocketServer.BaseRequestHandler).serve_forever()"

Copy all files. All normal files, all hidden files and all files starting with - (minus).
./* is for copying files starting with - .[!.]* is for copying hidden files and avoiding copying files from the parent directory. ..?* is for copying files starting with .. (avoids the directory ..) /path/to/dir the path to the directory where the files should be copied Can also be used as a script. Input argument is /path/to/dir in tcsh, replace .[!.]* with .[^.]*

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Get Dollar-Euro exchage rate
You can get others rates changing the "EUR/US" part. look at the url: wap.kitco.com/exrate.wml to get more options.

Prefix every line with a timestamp
Useful to add a timestamp to every line printed to stdout. You can use `-Ins` instead of `-Iseconds` if you want more precision.

Check if the LHC has destroyed the world
This says if the LHC has destroyed the world. Run it in a loop to monitor the state of Earth. Might not work reliable, if the world has actually been destroyed.

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.

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