Commands by marcelduran (0)

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What's this? is the place to record those command-line gems that you return to again and again. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.

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Show drive names next to their full serial number (and disk info)
As of this writing, this requires a fairly recent version of util-linux, but is much simpler than the previous alternatives. Basically, lsblk gives a nice, human readable interface to all the blkid stuff. (Of course, I wouldn't recommend this if you're going to be parsing the output.) This command takes all the fun out of the previous nifty pipelines, but I felt I ought to at least mention it as an alternative since it is the most practical.

Tar files matching a certain wildcard
This is a shortcut to tar up all files matching a wildcard. Tar doesn't have the --include (apparently).

Get AWS temporary credentials ready to export based on a MFA virtual appliance
You might want to secure your AWS operations requiring to use a MFA token. But then to use API or tools, you need to pass credentials generated with a MFA token. This commands asks you for the MFA code and retrieves these credentials using AWS Cli. To print the exports, you can use: `awk '{ print "export AWS_ACCESS_KEY_ID=\"" $1 "\"\n" "export AWS_SECRET_ACCESS_KEY=\"" $2 "\"\n" "export AWS_SESSION_TOKEN=\"" $3 "\"" }'` You must adapt the command line to include: * $MFA_IDis ARN of the virtual MFA or serial number of the physical one * TTL for the credentials

Text graphing ping output filter
Nasty perl one-liner that provides a sparkline of ping times. If you want a different history than the last 30, just put that value in. It (ab)uses unicode to draw the bars, inspired by . It's not the most bug-free piece of code, but what it lacks in robustness it makes up for in capability. :) If anyone has any ideas on how to make it more compact or better, I'd love to hear them. I included a ping to google in the command just as an example (and burned up 10 chars doing it!). You should use it with: $ ping | $SPARKLINE_PING_COMMAND

Print process run time, average CPU usage, and maximum memory usage on exit
Bash has a built-in time command which provides less functionality than the real time command. Thus we reference /usr/bin/time directly. Since the command isn't very easy to remember you could alias it to something like "cputime" or even just "time".

Convert a mp3 file to m4a
I use this to convert mp3 files to m4a files that can be used as ringtones on the iPhone. I've documented the process here:

awk change field separator
GNU Awk 3.1.4

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"

Securely destroy data on given device hugely faster than /dev/urandom
This command generates a pseudo-random data stream using aes-256-ctr with a seed set by /dev/urandom. Redirect to a block device for secure data scrambling.

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