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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

resize all JPG images in folder and create new images (w/o overwriting)
Convert all jpegs in the current directory into ~1024*768 pixels and ~ 150 KBytes jpegs

return external ip
Get your ip address, hostname, ASN and geolocation information. If you want just one field as a text response you can also get that,eg curl ipinfo.io/ip

Execute a command without saving it in the history
Yes, by correctly setting the HIST* variables you can make certain commands not saved in history. But that's complicated and easy to make a mistake. If you set HISTFILE= to blank, nothing in your current shell session will be saved in history. Although this is not a precise answer to the subject, but it's very simple.

parted - scripted partitioning (of all multipathed SAN LUNs)
`multipath -ll` requires Device Mapper multipath.conf configuration. And of course, replace "3PARdata,VV" with your disk array's SCSI vendor,LUN name. - GPT partition table allows you to create >2TB partitions

using `!#$' to referance backward-word
expand to: cp /work/host/phone/ui/main.cpp /work/target/phone/ui/main.cpp !# The entire command line typed so far.

exim statistics about mails from queue
statistics are sorted based on number of recipients.

finding cr-lf files aka dos files with ^M characters
Looking for carriage returns would also identify files with legacy mac line endings. To fix both types: $ perl -i -pe 's/\r\n?/\n/g' $(find . -type f -exec fgrep -l $'\r' "{}" \;)

Intercept, monitor and manipulate a TCP connection.
Forwards localhost:1234 to machine:port, running all data through your chain of piped commands. The above command logs inbound and outbound traffic to two files. Tip: replace tee with sed to manipulate the data in real time (use "sed -e 's/400 Bad Request/200 OK/'" to tweak a web server's responses ;-) Limitless possibilities.

loop over a set of items that contain spaces
If you want to operate on a set of items in Bash, and at least one of them contains spaces, the `for` loop isn't going to work the way you might expect. For example, if the current dir has two files, named "file" and "file 2", this would loop 3 times (once each for "file", "file", and "2"): $ for ITEM in `ls`; do echo "$ITEM"; done Instead, use a while loop with `read`: $ ls | while read ITEM; do echo "$ITEM"; done


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