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Add your public SSH key to a server in one command
Just run the command, type your password, and that's the last time you need to enter your password for that server. This assumes that the server supports publickey authentication. Also, the permissions on your home dir are 755, and the permissions on your .ssh dir are 700 (local and remote).

Reuse last parameter
Reuse the last parameter of the previous command line

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

tcpdump from src to dst
then open with wireshark

distribution specific information

Remove CR LF from a text file
Remove CR LF (CRLF) from a text file. use man:tr to get more info about removing other characters from a file. and even character to character replacements.

Write comments to your history.
A null operation with the name 'comment', allowing comments to be written to HISTFILE. Prepending '#' to a command will *not* write the command to the history file, although it will be available for the current session, thus '#' is not useful for keeping track of comments past the current session.

Use wget to download one page and all it's requisites for offline viewing

Install pip with Proxy
Installs pip packages defining a proxy


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