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Multi-segment file downloading with lftp
This is for files only, for directories 'mirror' has to be used.

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" }

Generate list of words and their frequencies in a text file.

check open ports without netstat or lsof

Redirect STDIN
Several times, I find myself hitting my up arrow, and changing the search term. Unfortunately, I find myself wasting too much time typing: $ grep kernel /var/log/messages Redirecting STDIN allows me to put the search term at the end so I less cursor movement to change what I'm searching for: $ < /var/log/messages grep kernel If you're using the emacs keyboard binding, then after you press your up arrow, press CTRL+w to erase the word. If this has already been submitted, I couldn't find it with the search utility.

Quick glance at who's been using your system recently
This command takes the output of the 'last' command, removes empty lines, gets just the first field ($USERNAME), sort the $USERNAMES in reverse order and then gives a summary count of unique matches.

Conficker Detection with NMAP

parrallel execution of a command on remote hosts by ssh or rsh or ...
parrallel execution of a command on remote host by ssh or rsh or ... very useful for cluster management (software update)

start a tunnel from some machine's port 80 to your local post 2001
now you can acces the website by going to http://localhost:2001/

Quick screenshot
Requires ImageMagick. Takes a screenshot 5 seconds after it's run and saves it as desktop_screenshot.jpg Particularly handy when made into a menu option or button.


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