1. cut
Ex. #echo “192.168.1.10:8080″| cut -d: -f1
192.168.1.10
Ex. User with uniq & sort
Ex. #netstat -nap|less|grep ‘192.168’| awk ‘{print $5}’|uniq -c|sort -nr -k 1
2. sed
match a string and replace it
echo “I love poem”|sed ‘s/peom/music/’
A funny and good poem
Sometimes it’s preferred to install libraries into non-default locations, such as /usr/local/,
but how to let the system know where to find them?
ldconfig can be used to change the lib path,
Ex. To have the system be able to find libraries under /usr/local/lib for myapp
vi /etc/ld.so.conf.d/myapp.conf
/usr/local/lib
#ldconfig
To check result
#ldconfig -v
# ldconfig -l /path/to/lib/missing.lib.so
Great articles about shared libraries.
http://www.cyberciti.biz/faq/linux-setting-changing-library-path/
http://www.cyberciti.biz/tips/linux-shared-library-management.html
Examples:
Show details of packets
#tcpdump -nnvvXS
tcpdump
show specific type of connection
#tcpdump icmp/tcp/udp
Add more options with source/destination IP/port, write to file
tcpdump -nnvvXS src 1.2.3.4 and port 3306 -w /tmp/test.pcap
Read tcpdump log from the file
tcpdump -qns -0 A -r /tmp/test.pcap
tcpick -C -yP -r /tmp/test.pcap
ngrep
ngrep -d any -W byline dst 1.2.3.4 > /tmp/test.pcap