How to stop tcpdump remotely using expect from a new telnet session
- by The CodeWriter
I am trying to stop the tcpdump command from running on a remote terminal. If I telnet to the terminal, start tcpdump, and then send a ^c, tcpdump stops with no issues. However if I telnet to the same terminal, start tcpdump, and then exit the telnet session, when I reconnect to the same telnet session I am unable to stop tcpdump via a ^c. When I do this instead of stopping tcpdump it seems that it just quits the telnet session and tcpdump continues to run on the remote terminal. I provided my script below. Any help is greatly appreciated.
#!/usr/local/bin/expect -f
exp_internal 1
set timeout 30
spawn /bin/bash
expect "] "
send "telnet 192.168.62.133 10006\r"
expect "Escape character is '^]'."
send "\r"
expect "# "
set now [clock format [clock seconds] -format {%d_%b_%Y_%H%M%S}]
set command "tcpdump -vv -i trf400 ip proto 89 -s 65535 -w /tmp/test_term420_${now}.pcp "
send "$command\r"
expect "tcpdump: listening on"
# This works correctly. tcpdump quits and I am returned to the expected prompt
send "\x03"
expect "# "
send "$command\r"
expect "tcpdump: listening on"
# Exit telnet session
send -- "\x1d"
expect "telnet> "
send -- "q\r"
expect "] "
# Reconnect to telnet session
send "telnet 192.168.62.133 10006\r"
expect "Escape character is '^]'."
send "\r"
# This does not work as intended. The ^c quits the telnet session instead of stopping tcpdump
send "\x03"
expect "] "
send "ls\r"
expect "] "
