Question

Part 1: netstat
Run the 'netstat' command and review the output. Note that the first part
of the output is a list of active Internet connections, and the second part
is a list of active sockets. The format of each part is different (i.e. different
number of columns per line, and different column headers).

1.  Write a bash command line that will display the number of active Internet
    connections as reported by 'netstat'.  Your output should be a single number.

2.  Write a bash command line that will display the number of active Internet
    connections with non-zero 'Send-Q' values, as reported by 'netstat'.  Your
    output should be a single number.

3.  Write a bash command line that will display the TOTAL of all 'Send-Q' values 
    for all active Internet connections reported by 'netstat'.  In other words, 
    calculate and display the numeric total of the 'Send-Q' column of the 'netstat'
    output. Your output should be a single number.

4.  Is the 'Foreign Address' reported by 'netstat' an internal or external address?
    Explain why.

5.  Write a bash command line that will display the 'I-Node' and 'State' values
    for all active UNIX domain sockets whose State is "CONNECTED" and whose "Path"
    value is empty (i.e. all spaces)

6.  Write a bash command line that will display the 'Type' and 'I-Node' values for
    all active UNIX domain sockets whose 'RefCnt' value is greater than 2.

Part 2: hostname
Review the 'man' documentation for 'hostname'.  

7.  Execute a 'hostname -i' command.  
    Is the IP address displayed by 'hostname' an internal or an external address?  
    Explay why.

Part 3: ping
Review the 'man' documetation for 'ping'.  
Execute a 'ping www.pcc.edu' command and review the output.

8.  Is the IP address shown for www.pcc.edu an internal or an external IP address?
    Explain why.

9.  Write a bash command line that will ping 'www.pcc.edu' 10 times, and then display
    the average ping time in milliseconds. Your output should be a single number.

Answer 1

1. Write a bash command line that will display the number of active Internet
    connections as reported by 'netstat'. Your output should be a single number.

   netstat | grep ESTABLISHED | wc | awk '{ print $1 }'

2. Write a bash command line that will display the number of active Internet
    connections with non-zero 'Send-Q' values, as reported by 'netstat'. Your
    output should be a single number.
  
   netstat | grep ESTABLISHED | awk '{ print $3 }' | grep -vcw 0
  

3. Write a bash command line that will display the TOTAL of all 'Send-Q' values
    for all active Internet connections reported by 'netstat'. In other words,
    calculate and display the numeric total of the 'Send-Q' column of the 'netstat'
    output. Your output should be a single number.

   netstat | grep ESTABLISHED | awk '{ print $3 }' | awk -F '|' '{sum+=$NF} END {print sum}'

5. Write a bash command line that will display the 'I-Node' and 'State' values
    for all active UNIX domain sockets whose State is "CONNECTED" and whose "Path"
    value is empty (i.e. all spaces)
  
   netstat | grep CONNECTED | awk '{if ($8) print $0;}' | awk '{ print $6 " " $7 }'

6. Write a bash command line that will display the 'Type' and 'I-Node' values for
    all active UNIX domain sockets whose 'RefCnt' value is greater than 2.

   netstat | grep CONNECTED | awk '{if ($2 > 2) print $0;}' | awk '{ print $5 " " $7 }'

9. Write a bash command line that will ping 'www.pcc.edu' 10 times, and then display
    the average ping time in milliseconds. Your output should be a single number.
  
   ping www.google.com -c 10 | grep rtt | awk '{print $4}' | cut -d / -f 2