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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" }

Send a binary file as an attachment to an email
The uuencode utility will encode your file so that it can be sent as an attachment to an email. It is part of the sharutils package in RHEL/CentOS/Fedora.

tar copy
Just a copy of a big dir when you wan't things like ownership and date etc etc to be untouched. Note: Updated with the ideas from "mpb".

What is my public IP address
Clean output, if used in scripts: $ GET checkip.dyndns.org|grep -o '[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}' or $ GET icanhazip.com

Detect illegal access to kernel space, potentially useful for Meltdown detection
Based on capsule8 agent examples, not rigorously tested

Fill the screen with randomly colored lines
This one-liner fills the screen with randomly colored lines.

Delete Mailer-Daemon messages

Unlock more space form your hard drive
This command changes the reserved space for privileged process on '/dev/sda' to 1 per cent.

use the previous commands params in the current command
Here the !!:1 will take the first parameter from the previous command. This can be used in conjunction with other history commands like ! and so on.

StopWatch, simple text, hh:mm:ss using Unix Time
Works on real time clock, unix time based, decrementing the actual time from initial time saved in an environment variable exported to child process inside watch Shows elapsed time from start of script in hh:mm:ss format Non afected by system slow down due to the use of date.


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