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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" }

Periodically run a command without hangups, and send the output to your e-mail
Run "ps -x" (process status) in the background every hour (in this example). The outputs of both "nohup" and "ps -x" are sent to the e-mail (instead of nohup.out and stdout and stderr). If you like it, replace "ps -x" by the command of your choice, replace 3600 (1 hour) by the period of your choice. You can run the command in the loop any time by killing the sleep process. For example $ ps -x 2925 ? S 0:00.00 sh -c unzip E.zip >/dev/null 2>&1 11288 ? O 0:00.00 unzip E.zip 25428 ? I 0:00.00 sleep 3600 14346 pts/42- I 0:00.01 bash -c while true; do ps -x | mail (...); sleep 3600; done 643 pts/66 Ss 0:00.03 -bash 14124 pts/66 O+ 0:00.00 ps -x $ kill 25428 You have mail in /mail/(...)

Find usb device in realtime
Using this command you can track a moment when usb device was attached.

Listing today’s files only

Perl one-liner to determine number of days since the Unix epoch
There are some environments that use this value for password and account expiration. It's helpful to be able to quickly determine the number of days since the Unix epoch (dse) when working directly with the configuration files as an administrator.

easily strace all your apache processes
Will open strace on all apache process, on systems using sbin/apache (debian) or sbin/httpd (redhat), and will follow threads newly created.

Execute a command, convert output to .png file, upload file to imgur.com, then returning the address of the .png.
My key is the anonymous one, is good for 50 post an hour with a maximun number of uploads a day, probably will run out, if that happend you can get a free key at the site.

Remove security limitations from PDF documents using ghostscript
Remove security from PDF document using this very simple command on Linux and OSX. You need ghostscript for this baby to work.

url shortner using google's shortner api
First get a api key for google url shortner from here https://developers.google.com/url-shortener/ Then replace the API_KEY in the command

Delete empty directories
Recursively delete empty directories. Use with care.


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