To view the number of connections

# Netstat-an | awk '/^tcp/{++s[$NF]} END {for (a in S) print A, s[a]} '
Time_wait 22387
Close_wait 11
Syn_sent 1
Fin_wait1 1
Established 423
LISTEN 73

# Netstat-n | awk '/^tcp/{++s[$NF]} END {for (a in S) print A, s[a]} '
Time_wait 21394
Close_wait 16
Fin_wait1 1
Established 423

==========================

# netstat-n|grep "^tcp" |awk ' {print $NF} ' |sort-n|uniq-c|sort-n
Close_wait
423 established
22670 time_wait

# netstat-an|grep "^tcp" |awk ' {print $NF} ' |sort-n|uniq-c|sort-n
1 fin_wait1
Close_wait
LISTEN
421 established
20296 time_wait

difference: The above two differences are Netstat-an and Netstat-n where a represents the full state, including the current port listening state,-n only represents the current connection state.

Parameter description:
CLOSED: No connection is active or in progress
LISTEN: The server is waiting to enter the call
SYN_RECV: A connection request has arrived, waiting for confirmation
Syn_sent: Application has started, open a connection
Established: Normal data transfer status
FIN_WAIT1: Application says it's done
Fin_wait2: The other side has agreed to release
Itmed_wait: Waiting for all packets to die
CLOSING: Both sides try to close simultaneously
Time_wait: The other side has initialized a release
Last_ack: Waiting for all packets to die

To view the number of connections