Commands for the wicked (110)

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set history file length
set how many commands to keep in history Default is 500 Saved in /home/$USER/.bash_history Add this to /home/$USER/.bashrc HISTFILESIZE=1000000000 HISTSIZE=1000000

List of reverse DNS records for a subnet
This command uses nmap to perform reverse DNS lookups on a subnet. It produces a list of IP addresses with the corresponding PTR record for a given subnet. You can enter the subnet in CDIR notation (i.e. /24 for a Class C)). You could add "--dns-servers x.x.x.x" after the "-sL" if you need the lookups to be performed on a specific DNS server. On some installations nmap needs sudo I believe. Also I hope awk is standard on most distros.

Find the ratio between ram usage and swap usage.
it provides the ratio used for the RAM and The SWAP under Linux. When swappiness is high, Swap usage is high. When swappiness is low, Ram usage is high.

tail, with specific pattern colored

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 stress test
For each cpu set mask and then monitor your cpu infos. Temp,load avg. etc. For example for 2nd cpu or 2nd core taskset 0x00000002 yes > /dev/null & For example for 3rd cpu or 3rd core taskset 0x00000004 yes > /dev/null & For example for 4th cpu or 4th core taskset 0x00000008 yes > /dev/null & Monitor your cpu temp with this command if you want watch -n1 "acpi -t" Load avg. from top command top [email protected] http://www.bayner.com/

drill holes on image

save your current environment as a bunch of defaults

Open-iscsi target discovery

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.


Stay in the loop…

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