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cooking a list of numbers for calculation
When you've got a list of numbers each on its row, the ECHO command puts them on a simple line, separated by space. You can then substitute the spaces with an operator. Finally, pipe it to the BC program.

A line across the entire width of the terminal
Use tput cols to find the width of the terminal and set it as the minimum field width.

diff will usually only take one file from STDIN. This is a method to take the result of two streams and compare with diff. The example I use to compare two iTunes libraries but it is generally applicable.
diff is designed to compare two files. You can also compare directories. In this form, bash uses 'process substitution' in place of a file as an input to diff. Each input to diff can be filtered as you choose. I use find and egrep to select the files to compare.

List last opened tabs in firefox browser
Tuned for short command line - you can set the path to sessionstore.js more reliable instead of use asterixes etc. Usable when you are not at home and really need to get your actual opened tabs on your home computer (via SSH). I am using it from my work if I forgot to bookmark some new interesting webpage, which I have visited at home. Also other way to list tabs when your firefox has crashed (restoring of tabs doesn't work always). This script includes also tabs which has been closed short time before.

Find processes utilizing high memory in human readable format
Finding high memory usage report in human readable format.

Set laptop display brightness
Run as root. Path may vary depending on laptop model and video card (this was tested on an Acer laptop with ATI HD3200 video). $ cat /proc/acpi/video/VGA/LCD/brightness to discover the possible values for your display.

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" }

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

A nice command for summarising repeated information

Resolve the "all display buffers are busy, please try later" error on a Foundry


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