Commands by jonavon (2)

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Set blanket packet/second limit on network interface for Ubuntu VPS server
VPS server hosts suspect DOS attack if PPS is too high. This limits packets at the interface level. Do "sudo apt-get install iptables-persistent" to make persistent, or, if you already have, reconfigure with "sudo dpkg-reconfigure iptables-persistent"

Create a backup of file being edited while using vi
At the start of a vi session and *before* saving any changes use ":!cp % %-" to make a backup of the current file being edited. example: vi /data/some/long/path/file :!cp% %- creates /data/some/long/path/file-

generate iso

generate a random 10 character password
Generate a table of random 10 character passwords

Turning off display
To turn off monitor: xset dpms force off To turn on, simply press a key, or move mouse/mousepad.

Get list of servers with a specific port open
Change the -p argument for the port number. See "man nmap" for different ways to specify address ranges.

Install the Debian-packaged version of a Perl module
Running 'cpan Module::Name' will install that module from CPAN. This is a simple way of using a similar command to install a packaged Perl module from a Debian archive using apt-get.

Diff on two variables
You got some results in two variables within your shell script and would like to find the differences? Changes in process lists, reworked file contents, ... . No need to write to temporary files. You can use all the diff parameters you'll need. Maybe anything like $ grep "^>" is helpful afterwards.

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" }

cpu info


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