Commands using head (314)

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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" }

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

exec chmod to subfiles
Using `-exec cmd {} +` causes find to build the command using all matching filenames before execution, rather than once per file.

list block devices
Shows all block devices in a tree with descruptions of what they are.

lotto generator

Search files with js declarations inside
Useful to crawl where the javascript is declared, and extract it a common file. You can redirect it to a file to review item by item.

Reducing image size
Adding the exclamation mark to the image geometry ignores the original aspect ratio. More info about image geometry: http://www.imagemagick.org/script/command-line-processing.php#geometry

To find which host made maximum number of specific tcp connections
This command is primarily going to work on linux boxes. and needs to be changed, for example IP=10\.194\.194\.2 PORT=389

Command to logout all the users in one command
It's only to logout all other user's except "root"

Calculate days on which Friday the 13th occurs (inspired from the work of the user justsomeguy)
Friday is the 5th day of the week, monday is the 1st. Output may be affected by locale.


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