Commands using ssh-keygen (31)

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execute your commands and avoid history records
$ secret_command;export HISTCONTROL= This will make "secret_command" not appear in "history" list.

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

Convert CSV to JSON
Replace 'csv_file.csv' with your filename.

ls not pattern
Hides some entries from listing.

Get the IP address

Suspend to ram

Port scan a range of hosts with Netcat.
Simple one-liner for scanning a range of hosts, you can also scan a range of ports with Netcat by ex.: nc -v -n -z -w 1 192.168.0.1 21-443 Useful when Nmap is not available:) Range declaration like X..X "for i in {21..29}" is only works with bash 3.0+

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"

Merge PDFs with Ghostscript wrapped in a function
This is an expansion on a previous entry, which I've wrapped in a function and placed in my profile. The "[email protected]" is a positional parameter, much like "$*", but the parameters are passed on intact, without interpretation or expansion; so you can simply call the function like this: mergepdf * This will output a merged PDF of all PDFs in the current directory. Alternatively, you can simply list them like so: mergepdf 00.pdf 01.pdf 02.pdf ... N.B. Passing a wildcard will merge all PDFs in the current directory in name order, e.g. 00.pdf 01.pdf aa.pdf ab.pdf

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" }


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