[youtube https://www.youtube.com/watch?v=IkmjCmvfeFI?rel=0&w=560&h=315]
How we conquered the deadly smallpox virus – Simona Zompi
[youtube https://www.youtube.com/watch?v=yqUFy-t4MlQ?rel=0&w=560&h=315]
The deadly irony of gunpowder – Eric Rosado
[youtube https://www.youtube.com/watch?v=mqHVRgCkCDE?rel=0&w=640&h=480]
Understanding a WordPress Plugin
<?php
/*
Plugin Name: Yet Another Search Meddle
Plugin URI:
Version: 0.1
Author: Jeffrin Jose T and Public Domain
Author URI: http://linkedin.com/in/jeffrinl
Description: modifying the way search results are displayed
*/
function resultsperpage($limits) {
/* resultsperpage - it is a custom created php function. */
if (is_search()) {
/* is_search() - it is an inbuilt php function in wordpress */
/* http://codex.wordpress.org/Function_Reference/is_search */
return 'LIMIT 0, 25';
}
return $limits;
}
add_filter('post_limits', 'resultsperpage');
/* post_limits - a wordpress hook ( a filter hook ) */
/* http://codex.wordpress.org/Plugin_API/Filter_Reference/post_limits */
/* add_filter - Hook a function to a specific filter action. */
/* http://codex.wordpress.org/Function_Reference/add_filter */
Crash: glibc: compile from upstream source related
Log Report Related
the following content may not be accurate.
1. unable to find getty program upstream source. 2. need to get libc-2.14 for getty. 3. trying to upgrade another system to get libc-2.14 4. is it possible to get multiple versions of glibc installed on a same system. compile another version of glibc and just take the necessary files and copy into into may be /lib 5. a new method of installing package using apt-get apt-get install libc6-dev=2.17-7 apt-show-versions -a -p libc6
Debug Methods
1. update LD_LIBRARY_PATH with the old and new path of libraries installed 2. use debian disc wit rescue mode and try to fix libraries with matching versions of libraries with new glibc 3. add proper symlinks for the new libraries under glibc 4. try to make a separate installation of debian in another(may be swap of the crashed debian ) and try to chroot to crashed debian root and try to fix the errors. 5. try to find out where to set LD_LIBRARY_PATH by default automatically. 6. if chroot is success related, then try to apt-get upgrade the crashed debian so that it may fix other errors automatically.
Maths : What is a Function : y=f(x)
commandline session and notes related may be engineering functions related. suppose y=f(x). y = output. suppose i equate y to ls ls is a GNU command. ls contains different methods(ingredients) which form ls command. suppose i write ls = f (-a,-i,-l,...) different cases : 1. y = -a 2. y = -al 3. y = -l, 4. y = -i 5. y = -ail $ls -ail total 1708 3673124 drwxr-xr-x 4 jeffrin jeffrin 4096 Nov 27 20:18 . 3670018 drwxr-xr-x 48 jeffrin jeffrin 4096 Nov 27 19:13 .. 3804877 drwxr-xr-x 2 jeffrin jeffrin 4096 Nov 22 21:40 direct 3670534 lrwxrwxrwx 1 jeffrin jeffrin 7 Nov 22 21:41 directlink -> direct/ 3673719 -rw-r--r-- 1 jeffrin jeffrin 104 Nov 15 20:50 file 3805205 drwx------ 2 jeffrin jeffrin 4096 Nov 25 20:18 Mail 3671094 -rw-r--r-- 1 jeffrin jeffrin 1710918 Nov 25 02:23 out.ogv 3673430 -rw-r--r-- 1 jeffrin jeffrin 7946 Nov 25 01:55 shelr-record.json 3673230 -rw-r--r-- 1 jeffrin jeffrin 217 Nov 27 20:16 tmp 3672617 lrwxrwxrwx 1 jeffrin jeffrin 30 Nov 27 20:18 .#tmp -> jeffrin@debian.5024:1385559781 3673193 -rw-r--r-- 1 jeffrin jeffrin 1 Nov 27 19:54 tmp~ $ls -a . .. direct directlink file Mail out.ogv shelr-record.json tmp .#tmp tmp~ $ls -i 3804877 direct 3673719 file 3671094 out.ogv 3673230 tmp 3670534 directlink 3805205 Mail 3673430 shelr-record.json 3673193 tmp~ $ls -l total 1700 drwxr-xr-x 2 jeffrin jeffrin 4096 Nov 22 21:40 direct lrwxrwxrwx 1 jeffrin jeffrin 7 Nov 22 21:41 directlink -> direct/ -rw-r--r-- 1 jeffrin jeffrin 104 Nov 15 20:50 file drwx------ 2 jeffrin jeffrin 4096 Nov 25 20:18 Mail -rw-r--r-- 1 jeffrin jeffrin 1710918 Nov 25 02:23 out.ogv -rw-r--r-- 1 jeffrin jeffrin 7946 Nov 25 01:55 shelr-record.json -rw-r--r-- 1 jeffrin jeffrin 217 Nov 27 20:16 tmp -rw-r--r-- 1 jeffrin jeffrin 1 Nov 27 19:54 tmp~ $
common network utilities/tools
commandline session
$ping www.beautifulwork.org PING beautifulwork.org (46.22.210.18) 56(84) bytes of data. 64 bytes from mars.infoclub.in (46.22.210.18): icmp_req=1 ttl=53 time=310 ms 64 bytes from mars.infoclub.in (46.22.210.18): icmp_req=2 ttl=53 time=210 ms 64 bytes from mars.infoclub.in (46.22.210.18): icmp_req=3 ttl=53 time=210 ms 64 bytes from mars.infoclub.in (46.22.210.18): icmp_req=4 ttl=53 time=210 ms 64 bytes from mars.infoclub.in (46.22.210.18): icmp_req=5 ttl=53 time=211 ms ^C --- beautifulwork.org ping statistics --- 5 packets transmitted, 5 received, 0% packet loss, time 4069ms rtt min/avg/max/mdev = 210.503/230.707/310.307/39.800 ms $ping -c 2 www.beautifulwork.org PING beautifulwork.org (46.22.210.18) 56(84) bytes of data. 64 bytes from mars.infoclub.in (46.22.210.18): icmp_req=1 ttl=53 time=302 ms 64 bytes from mars.infoclub.in (46.22.210.18): icmp_req=2 ttl=53 time=209 ms --- beautifulwork.org ping statistics --- 2 packets transmitted, 2 received, 0% packet loss, time 1000ms rtt min/avg/max/mdev = 209.468/256.133/302.799/46.668 ms $ping -c 2 -i 1 www.beautifulwork.org PING beautifulwork.org (46.22.210.18) 56(84) bytes of data. 64 bytes from mars.infoclub.in (46.22.210.18): icmp_req=1 ttl=53 time=328 ms 64 bytes from mars.infoclub.in (46.22.210.18): icmp_req=2 ttl=53 time=347 ms --- beautifulwork.org ping statistics --- 2 packets transmitted, 2 received, 0% packet loss, time 1000ms rtt min/avg/max/mdev = 328.452/337.938/347.425/9.504 ms $netstat -ntl Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State tcp 0 0 0.0.0.0:45517 0.0.0.0:* LISTEN tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN tcp6 0 0 :::111 :::* LISTEN tcp6 0 0 :::22 :::* LISTEN tcp6 0 0 ::1:25 :::* LISTEN tcp6 0 0 :::51975 :::* LISTEN $netstat -ntlp (Not all processes could be identified, non-owned process info will not be shown, you would have to be root to see it all.) Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 0.0.0.0:45517 0.0.0.0:* LISTEN - tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN - tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN - tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN - tcp6 0 0 :::111 :::* LISTEN - tcp6 0 0 :::22 :::* LISTEN - tcp6 0 0 ::1:25 :::* LISTEN - tcp6 0 0 :::51975 :::* LISTEN - $sudo netstat -ntlp [sudo] password for jeffrin: Active Internet connections (only servers) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 0.0.0.0:45517 0.0.0.0:* LISTEN 1859/rpc.statd tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN 1828/rpcbind tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 3099/sshd tcp 0 0 127.0.0.1:25 0.0.0.0:* LISTEN 27100/exim4 tcp6 0 0 :::111 :::* LISTEN 1828/rpcbind tcp6 0 0 :::22 :::* LISTEN 3099/sshd tcp6 0 0 ::1:25 :::* LISTEN 27100/exim4 tcp6 0 0 :::51975 :::* LISTEN 1859/rpc.statd $sudo netstat -n
GNU/Linux Common Network Utilities/Tools – Video Tutorial Related
[source : http://www.youtube.com/user/frankperez87]
[youtube https://www.youtube.com/watch?v=CigJXmUYXJY?rel=0&w=853&h=480]
nmap . -O: Enable OS detection
commandline session
$nmap 127.0.0.1 Starting Nmap 6.00 ( http://nmap.org ) at 2013-11-24 17:56 IST Nmap scan report for localhost (127.0.0.1) Host is up (0.00019s latency). Not shown: 997 closed ports PORT STATE SERVICE 22/tcp open ssh 25/tcp open smtp 111/tcp open rpcbind Nmap done: 1 IP address (1 host up) scanned in 0.10 seconds $nmap -O 127.0.0.1 TCP/IP fingerprinting (for OS scan) requires root privileges. QUITTING! $sudo nmap -O 127.0.0.1 [sudo] password for jeffrin: Starting Nmap 6.00 ( http://nmap.org ) at 2013-11-24 17:56 IST Nmap scan report for localhost (127.0.0.1) Host is up (0.000057s latency). Not shown: 997 closed ports PORT STATE SERVICE 22/tcp open ssh 25/tcp open smtp 111/tcp open rpcbind No exact OS matches for host (If you know what OS is running on it, see http://nmap.org/submit/ ). TCP/IP fingerprint: OS:SCAN(V=6.00%E=4%D=11/24%OT=22%CT=1%CU=32670%PV=N%DS=0%DC=L%G=Y%TM=5291F0 OS:7A%P=x86_64-unknown-linux-gnu)SEQ(SP=FF%GCD=1%ISR=111%TI=Z%CI=Z%II=I%TS= OS:8)OPS(O1=M400CST11NW6%O2=M400CST11NW6%O3=M400CNNT11NW6%O4=M400CST11NW6%O OS:5=M400CST11NW6%O6=M400CST11)WIN(W1=8000%W2=8000%W3=8000%W4=8000%W5=8000% OS:W6=8000)ECN(R=Y%DF=Y%T=41%W=8018%O=M400CNNSNW6%CC=Y%Q=)T1(R=Y%DF=Y%T=41% OS:S=O%A=S+%F=AS%RD=0%Q=)T2(R=N)T3(R=N)T4(R=Y%DF=Y%T=41%W=0%S=A%A=Z%F=R%O=% OS:RD=0%Q=)T5(R=Y%DF=Y%T=41%W=0%S=Z%A=S+%F=AR%O=%RD=0%Q=)T6(R=Y%DF=Y%T=41%W OS:=0%S=A%A=Z%F=R%O=%RD=0%Q=)T7(R=Y%DF=Y%T=41%W=0%S=Z%A=S+%F=AR%O=%RD=0%Q=) OS:U1(R=Y%DF=N%T=41%IPL=164%UN=0%RIPL=G%RID=G%RIPCK=G%RUCK=G%RUD=G)IE(R=Y%D OS:FI=N%T=41%CD=S) Network Distance: 0 hops OS detection performed. Please report any incorrect results at http://nmap.org/submit/ . Nmap done: 1 IP address (1 host up) scanned in 12.17 seconds $ $sudo nmap -O 192.168.0.1 Starting Nmap 6.00 ( http://nmap.org ) at 2013-11-24 17:59 IST Nmap scan report for 192.168.0.1 Host is up (0.00047s latency). Not shown: 998 closed ports PORT STATE SERVICE 53/tcp open domain 80/tcp open http MAC Address: 5C:D9:98:5C:01:1A (D-Link) Device type: general purpose Running: Linux 2.6.X OS CPE: cpe:/o:linux:kernel:2.6 OS details: Linux 2.6.29 - 2.6.31 Network Distance: 1 hop OS detection performed. Please report any incorrect results at http://nmap.org/submit/ . Nmap done: 1 IP address (1 host up) scanned in 2.10 seconds $
nmap . -O: Enable OS detection – Video Tutorial Related
[source : http://www.youtube.com/user/metalx1000 ]
[youtube https://www.youtube.com/watch?v=XaCzpqIU5-A?rel=0&w=560&h=315]
What does the command “netstat ” do ?
ABOUT netstat
In computing, netstat (network statistics) is a command-line network utility tool that displays network connections for the Transmission Control Protocol (both incoming and outgoing), routing tables, and a number of network interface (network interface controller or software-defined network interface) and network protocol statistics. It is available on Unix-like operating systems including macOS, Linux, Solaris, and BSD, and is available on Windows NT-based operating systems including Windows XP, Windows Vista, Windows 7, Windows 8 and Windows 10. It is used for finding problems in the network and to determine the amount of traffic on the network as a performance measurement.[1] On Linux this program is mostly obsolete, although still included in many distributions. On Linux, netstat (part of "net-tools") is superseded by ss (part of iproute2). Replacement for netstat -r is ip route. Replacement for netstat -i is ip -s link, replacement for netstat -g is ip maddr, all of which are recommended instead
RELATED SHELL SESSION EXPOSURE
[bash light=”true”]
$netstat –tcp
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 debian.local:39585 74.125.169.8:http ESTABLISHED
tcp 0 0 debian.local:39586 74.125.169.8:http ESTABLISHED
tcp 0 0 debian.local:47951 maa03s17-in-f6.1e:https ESTABLISHED
tcp 0 0 debian.local:47203 maa03s17-in-f0.1e1:http ESTABLISHED
$
$netstat –tcp –numeric
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 1 0 192.168.0.101:54541 46.22.210.18:80 CLOSE_WAIT
tcp 0 0 192.168.0.101:54542 46.22.210.18:80 ESTABLISHED
tcp 0 0 192.168.0.101:39585 74.125.169.8:80 ESTABLISHED
tcp 0 0 192.168.0.101:39586 74.125.169.8:80 TIME_WAIT
tcp 0 0 192.168.0.101:47951 74.125.236.198:443 ESTABLISHED
tcp 0 0 192.168.0.101:47203 74.125.236.192:80 ESTABLISHED
$netstat –tcp –numeric
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 192.168.0.101:54542 46.22.210.18:80 TIME_WAIT
tcp 0 0 192.168.0.101:39585 74.125.169.8:80 ESTABLISHED
tcp 0 0 192.168.0.101:39586 74.125.169.8:80 TIME_WAIT
tcp 0 0 192.168.0.101:47951 74.125.236.198:443 ESTABLISHED
tcp 0 0 192.168.0.101:47203 74.125.236.192:80 ESTABLISHED
$netstat –tcp –listen
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 *:35436 *:* LISTEN
tcp 0 0 *:sunrpc *:* LISTEN
tcp 0 0 *:ssh *:* LISTEN
tcp 0 0 localhost:smtp *:* LISTEN
tcp6 0 0 [::]:sunrpc [::]:* LISTEN
tcp6 0 0 [::]:501100 [::]:* LISTEN
tcp6 0 0 [::]:ssh [::]:* LISTEN
tcp6 0 0 localhost:smtp [::]:* LISTEN
$netstat –tcp –listen
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 *:35436 *:* LISTEN
tcp 0 0 *:sunrpc *:* LISTEN
tcp 0 0 *:ssh *:* LISTEN
tcp 0 0 localhost:smtp *:* LISTEN
tcp6 0 0 [::]:sunrpc [::]:* LISTEN
tcp6 0 0 [::]:501100 [::]:* LISTEN
tcp6 0 0 [::]:ssh [::]:* LISTEN
tcp6 0 0 localhost:smtp [::]:* LISTEN
$netstat –tcp –program
(Not all processes could be identified, non-owned process info
will not be shown, you would have to be root to see it all.)
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 debian.local:39600 74.125.169.8:http ESTABLISHED 3846/chrome
tcp 0 0 debian.local:47951 maa03s17-in-f6.1e:https ESTABLISHED 3846/chrome
tcp 0 0 debian.local:47203 maa03s17-in-f0.1e1:http ESTABLISHED 3846/chrome
$
$netstat –tcp –route
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface
default 192.168.0.1 0.0.0.0 UG 0 0 0 eth0
192.168.0.0 * 255.255.255.0 U 0 0 0 eth0
$netstat –tcp –statistics
IcmpMsg:
OutType3: 1
Tcp:
522 active connections openings
0 passive connection openings
14 failed connection attempts
16 connection resets received
2 connections established
60302 segments received
41524 segments send out
22 segments retransmited
21 bad segments received.
140 resets sent
UdpLite:
TcpExt:
190 TCP sockets finished time wait in fast timer
495 delayed acks sent
1 delayed acks further delayed because of locked socket
Quick ack mode was activated 32 times
47899 packet headers predicted
1353 acknowledgments not containing data payload received
406 predicted acknowledgments
7 congestion windows recovered without slow start after partial ack
22 other TCP timeouts
32 DSACKs sent for old packets
3 DSACKs sent for out of order packets
5 DSACKs received
25 connections reset due to unexpected data
16 connections reset due to early user close
TCPSackShiftFallback: 2
TCPChallengeACK: 21
TCPSYNChallenge: 21
IpExt:
InMcastPkts: 929
OutMcastPkts: 42
InBcastPkts: 16
OutBcastPkts: 14
InOctets: 83827635
OutOctets: 2776707
InMcastOctets: 332300
OutMcastOctets: 5264
InBcastOctets: 1808
OutBcastOctets: 1006
$
[/bash]
LINKS
https://en.wikipedia.org/wiki/Netstat
https://stackoverflow.com/tags/netstat/info
Bash – netstat ( network statistics related ) – Video Tutorial Related
[ source : http://www.youtube.com/user/metalx1000 ]
[youtube https://www.youtube.com/watch?v=wcrQgKNUD10?rel=0&w=560&h=315]
GNU/Linux BASH builtin commands
commandline session
$pwd
/home/jeffrin/playground
$which pwd
/bin/pwd
$
$/bin/pwd
/home/jeffrin/playground
$/bin/pwd -P
/home/jeffrin/playground
$pwd -P
/home/jeffrin/playground
$help pwd
pwd: pwd [-LP]
Print the name of the current working directory.
Options:
-L print the value of $PWD if it names the current working
directory
-P print the physical directory, without any symbolic links
By default, `pwd' behaves as if `-L' were specified.
Exit Status:
Returns 0 unless an invalid option is given or the current directory
cannot be read.
$mkdir direct
$ln -s direct/ directlink
$pwd
/home/jeffrin/playground
$cd direct
$pwd
/home/jeffrin/playground/direct
$pwd -P
/home/jeffrin/playground/direct
$/bin/pwd
/home/jeffrin/playground/direct
$/bin/pwd -P
/home/jeffrin/playground/direct
$cd ..
$cd directlink
$pwd
/home/jeffrin/playground/directlink
$pwd -P
/home/jeffrin/playground/direct
$/bin/pwd
/home/jeffrin/playground/direct
$/bin/pwd -P
/home/jeffrin/playground/direct
$/bin/pwd --help
Usage: /bin/pwd [OPTION]...
Print the full filename of the current working directory.
-L, --logical use PWD from environment, even if it contains symlinks
-P, --physical avoid all symlinks
--help display this help and exit
--version output version information and exit
NOTE: your shell may have its own version of pwd, which usually supersedes
the version described here. Please refer to your shell's documentation
for details about the options it supports.
Report pwd bugs to bug-coreutils@gnu.org
GNU coreutils home page:
General help using GNU software:
For complete documentation, run: info coreutils 'pwd invocation'
$pwd --help
bash: pwd: --: invalid option
pwd: usage: pwd [-LP]
$
GNU/Linux BASH builtin commands – Video Tutorial Related
[ source : http://www.youtube.com/user/theurbanpenguin ]
[youtube https://www.youtube.com/watch?v=Kv42Beohmyo?rel=0&w=560&h=315]