Commands using diff (119)

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Create a 5 MB blank file via a seek hole
Similar to the original, but is much faster since it only needs to write the last byte as zero. A diff on testfile and testfile.seek will return that they are the same.

Backup a local drive into a file on the remote host via ssh

Real time duplication of Apache app traffic to a second server
This takes the stream created by apache requests containing jsp and funnels them to another server. I'm using this for simulating real time traffic. The nice command gives ssh maximum CPU cycles, awk & grep strip out everything served by apache. Putting parallel on curl is important because curl is synchronous and waits for the response. Yes, I thought about using wget but it didn't seem any easier. Also, if you figure out how to run this in the background let me know. Every time I background it it stops. If you have multiple front end servers just run multiple instances of this.

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Find usb device in realtime
Using this command you can track a moment when usb device was attached.

Remove embedded fonts from a pdf.
It's sometimes useful to strip the embedded fonts from a pdf, for importing into something like Inkscape. Be warned, this will increase the size of a pdf substantially. I tried this with only gs writing with -sDEVICE=pdfwrite but it doesn't seem to work, so I just pipe postscript output to ps2pdf for the same effect.

Copy a file and force owner/group/mode
This is useful when you want to copy a file and also force a user, a group and a mode for that file. Note: if you want to move that file instead of copying it, you can use $install -o user -g group -m 755 /path/to/file /path/to/dir/ && rm -f /path/to/file which will remove the file only if the install command went fine.

Find all clients connected to HTTP or HTTPS ports
It finds, specifically, the connections to the HTTP and HTTPS ports as source ports. You can check for destination ports as well.

Keep one instance of an irc chat client in a screen session
This command attempts to attach to existing irssi session, if one exists, otherwise creates one. I use "irc" because I use different irc clients depending on what system I am working on. Consistency is queen.

Alternative way to generate an XKCD #936 style 4 word password usig sed
This is what I came up to generate XKCD #936 style four-word password. Since first letter of every word is capitalized it looks a bit more readable to my eyes. Also strips single quotes. And yes - regex is a bit of a kludge, but that's the bes i could think of.


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