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How to sum lines with decimals in awk
Read all lines using decimal marker as point, then add all them up and outputs the result.

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

Transfer a file to multiple hosts over ssh
You can push files to up to 32 servers at once assuming ssh keys are in place. Great tool, it is part of the pssh suite.

Convert seconds to [DD:][HH:]MM:SS
Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

set your ssd disk as a non-rotating medium
if you still get a permissions error using sudo, then nano the file: sudo nano -w /sys/block/sdb/queue/rotational and change 1 to 0 this thread: http://www.ocztechnologyforum.com/forum/showpost.php?p=369836&postcount=15 says that this will "help the block layer to optimize a few decisions"

Create Solid Archive (best compression) with 7z
Creates a solid archive with the highest possible compression (Ultra). Advantage of 7z is that it will use all the processor cores to create the archive. (Ok. at least version 9.04 does)

Find out how old a web page is
I is for headers only s is for silence curl -Is outputs ONLY headers the pipe and grep is to filter them to Modified only..

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: http://www.control-d.com/?p=60

encode HTML entities
Encodes HTML entities from input (file or stdin) so it's possible to directly past the result to a blog or HTML source file.

Send an email from the terminal when job finishes
Might as well include the status code it exited with so you know right away if it failed or not.


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