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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" }

Convert a single-page PDF to a hi-res PNG, at 300dpi
If you skip this part: $ -density 300x300 you'll get a very lo-res image.

copy root to new device
Clone a root partition. The reason for double-mounting the root device is to avoid any filesystem overlay issues. This is particularly important for /dev. Also, note the importance of the trailing slashes on the paths when using rsync (search the man page for "slash" for more details). rsync and bash add several subtle nuances to path handling; using trailing slashes will effectively mean "clone this directory", even when run multiple times. For example: run once to get an initial copy, and then run again in single user mode just before rebooting into the new disk. Using file globs (which miss dot-files) or leaving off the trailing slash with rsync (which will create /mnt/target/root) are traps that are easy to fall into.

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

Load your [git-controlled] working files into the vi arglist.
Branch name may be substituted, of course.

check open ports without netstat or lsof

Get absolut path to your bash-script
Another way of doing it that's a bit clearer. I'm a fan of readable code.

Search commandlinefu.com from the command line using the API
Usage: cmdfu hello world

create thumbnail of pdf

find out how much space are occuipied by files smaller than 1024K (sic) - improved
The original didn't use -print0 which fails on weird file names eg with spaces. The original parsed the output of 'ls -l' which is always a bad idea.


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