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Fast and easy way to find all established tcp connections without using the netstat command.
Shows which applications are making connections, and the addresses they're connecting to. Refreshes every 2 seconds (watch's default). Test on OSX, should work anywhere watch and lsof work.
also could specify port number:
lsof -ni TCP:80
Shows files and processes of the command php
See the summary.
This option is much faster, as it checks only network nodes.
This option selects the listing of all Internet and x.25 (HP-UX) network files.
Check open TCP and UDP ports
While `lsof` will work, why not use the tool designed explicitly for this job?
(If not run as root, you will only see the names of PID you own)
It may be helpful in case you need to umount a directory and some process is preventing you to do so keeping the folder busy. The lsof may process the +D option slowly and may require a significant amount of memory because it will descend the full dir tree. On the other hand it will neither follow symlinks nor other file systems.
Maybe this will help you to monitor your load balancers or reverse proxies if you happen to use them. This is useful to discover TIME OUTS and this will let you know if one or more of your application servers is not connected by checking.
In addition to generating the current connections, it also opens then in your default browser on gnome.
The output of lsof is piped to txt2html which converts it to html.
# Perl module HTML::TextToHTML needed
% lsof -v
lsof version information:
Where COMMAND is the process(es) name. I prefer to get all states but you may add ESTABLISHED in the grep regex.
lsof -c apache2 | egrep -o 'TCP.*ESTABLISHED.*$'
-nP flags are optional and UDP is irrelevant for established connections
Similar but using the process id:
lsof -nP -p PID | egrep -o '(TCP|UDP).*$'
Instead of using force un-mounting, it's better to find the processes that currently use the relevant folder.
for when a program is hogging the sound output. finds, and kills. add -9 to the end for wedged processes. add in 'grep ^program' after lsof to filter.
This command is more portable than it's cousin netstat. It works well on all the BSDs, GNU/Linux, AIX and Mac OS X. You won't find lsof by default on Solaris or HPUX by default, but packages exist around the web for installation, if needed, and the command works as shown. This is the most portable command I can find that lists listening ports and their associated pid.
When trying to play a sound you may sometimes get an error saying that your sound card is already used, but not by what process. This will list all processes playing sound, useful to kill processes that you no longer need but that keep using your sound card.
Just refining last proposal for this check, showing awk power to make more complex math (instead /1024/1024, 2^20). We don't need declare variable before run lsof, because $(command) returns his output. Also, awk can perform filtering by regexp instead to call grep. I changed the 0.0000xxxx messy output, with a more readable form purging all fractional numbers and files less than 1 MB.
show only the name of the apps that are using internet
Check which files are opened by Firefox then sort by largest size (in MB). You can see all files opened by just replacing grep to "/". Useful if you'd like to debug and check which extensions or files are taking too much memory resources in Firefox.