Commands using dmesg (15)

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"Pretty print" $PATH, show directories in $PATH, one per line with replacement pattern using shell parameter expansion
Can be used to create path alias. From: https://www.cyberciti.biz/tips/bash-aliases-mac-centos-linux-unix.html. #9

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" }

draw honeycomb
$ tput setaf 1 && tput rev && seq -ws "___|" 81|fold -69|tr "0-9" "_" && tput sgr0 $ $ # (brick wall)

Display a block of text: multi-line grep with perl
-n reads input, line by line, in a loop sending to $_ Equivalent to while () { mycode } -e execute the following quoted string (i.e. do the following on the same line as the perl command) the elipses .. operator behaves like a range, remembering the state from line to line.

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"

Backup with versioning
Apart from an exact copy of your recent contents, also keep all earlier versions of files and folders that were modified or deleted. Inspired by EVACopy http://evacopy.sourceforge.net

list files recursively by size

Suspend, background, and foreground a process
1. Start a process, such as 'top' command 2. # suspend process {ctrl-Z} 3. # background process bg 4. # list all backgrounded jobs jobs 5. # bring it back to foreground fg

Execute a command without saving it in the history
Prepending one or more spaces to your command won't be saved in history. Useful for pr0n or passwords on the commandline. Tested on BASH.

Localize provenance of current established connections
Sample command to obtain a list of geographic localization for established connections, extracted from netstat. Need geoiplookup command ( part of geoip package under CentOS)

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