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print first n characters of any file in human readble form using hexdump
Usefull to determine unknown file type

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

Limit bandwidth usage by apt-get
Limits the usage of bandwidth by apt-get, in the example the command will use 30Kb/s ;) It should work for most apt-get actions (install, update, upgrade, dist-upgrade, etc.)

Advanced python tracing
Trace python statement execution and syscalls invoked during that simultaneously

generate random tone

capture selected window

copy paste multiple binary files
Useful when you have multiple files or binary files that you need to transfer to a different host and scp or the like is unavailable. To unpack on the destination host copy paste output using the opposite order: openssl enc -d -base64 | gunzip | tar -x Terminate openssl input using ^d Note: gzip is outside of tar because using -z in tar produces lots of extra padding.

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Convert all WMF images to SVG recursively ignoring file extension case
This assumes you have the package installed necessary for converting WMF files. On my Ubuntu box, this is libwmf-bin. I used this command, as libwmf is not on my wife's iMac, so I archived the directories containing the WMF files from OS X, ran them on my Ubuntu box, archived the resulting SVGs, and sent them back to her. Quick, simple and to the point. Searches directories recursively looking for extensions ignoring case. This is much more readable and clean than -exec for find. The while loop also gives further flexibility on complex logic. Also, although there is 'wmf2svg --auto', it expects lowercase extensions, and not uppercase. Because I want to ignore case, I need to use the -o option instead. Works in ZSH and BASH. Haven't tested in other shells.

File rotation without rename command
Rotates log files with "gz"-extension in a directory for 7 days and enumerates the number in file name. i.e.: logfile.1.gz > logfile.2.gz I needed this line due to the limitations on AIX Unix systems which do not ship with the rename command.


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