Commands by PeekNPoke (0)

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This is how you should push a string in a command's stdin.
Don't do this: $echo word | command Using a bash "here strings" and "here documents" look leeter than piping echo into the command. Also prevents subshell execution. Word is also expanded as usual.

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

most used commands in history (comprehensive)
Most of the "most used commands" approaches does not consider pipes and other complexities. This approach considers pipes, process substitution by backticks or $() and multiple commands separated by ; Perl regular expression breaks up each line using | or < ( or ; or ` or $( and picks the first word (excluding "do" in case of for loops) note: if you are using lots of perl one-liners, the perl commands will be counted as well in this approach, since semicolon is used as a separator

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" }

Check if you work on a virtual/physical machine in Linux
Command used to know if we are working on a virtual or physical machine. This command will use the dmidecode utility to retrieve hardware information of your computer via the BIOS. Run this command as root or with sudo.

Command to logout all the users in one command
Only to logout all users except root

Multiline Search/Replace with Perl
from http://stackoverflow.com/questions/1030787/multiline-search-replace-with-perl added greedy trick in wildcard match (.*?) from http://www.troubleshooters.com/codecorn/littperl/perlreg.htm#Greedy

swap the java version being used
You have openjdk and sun java installed. Many of your java plugins will not work properly. Something called IcedTea (the java web plugin) keeps crashing. Run this and select sun java to use sun java.

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"

Get a list of ssh servers on the local subnet
--open -sV is not needed if you are only looking for hosts with 22 open


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