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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" }

Count Files in a Directory with Wildcards.
If the dir | wc -l Command not working.

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"

Print diagram of user/groups
Parses /etc/group to "dot" format and pases it to "display" (imagemagick) to show a usefull diagram of users and groups (don't show empty groups).

Kill any process with one command using program name
Somtime one wants to kill process not by name of executable, but by a parameter name. In such cases killall is not suitable method.

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"

Copy history from one terminal to another
Or just do history -w before opening another terminal.

Share a 'screen'-session
Ater person A starts his screen-session with `screen`, person B can attach to the srceen of person A with `screen -x`. Good to know, if you need or give support from/to others.

Sort a one-per-line list of email address, weeding out duplicates

command line fu roulette
retrieves the html from a random command line fu page, then finds commands on the page and prints them alternatively, pipe to bash (add "| bash" to the end) to execute the command (very risky) edit: had to adjust to properly display the portion that replaces HTML characters (e.g. " -> ")


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