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Display last exit status of a command
The variable ? contain the last exit status of a command, it can be printed for troubleshooting purpose.

What is my ip?

Currency Conversion
This works in Mac OS X (10.6.2) (natively comes with curl) usage: currency_convert $1(amount) $2(from_denomination) $3(to_denomination)

output length of longest line
If your wc does not have the -L option, you can use awk.

Use AWS CLI and JQ to get a list of instances sorted by launch time
You can do the filtering natively in the aws cli, without using jq (although jq is awesome!)

Finding the fingerprint of a given certificate

blktrace - generate traces of the i/o traffic on block devices
blktrace is a block layer IO tracing mechanism which provide detailed information about request queue operations up to user space. blkparse will combine streams of events for various devices on various CPUs, and produce a formatted output the the event information. It take the output of above tool blktrace and convert those information into fency readable form.

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" }

Count number of files in a directory

Edit a file in vim (at the first error) if it is not well formed xml.
Validate a file using xmllint. If there are parser errors, edit the file in vim at the line of the first error.


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