lsof
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lsof is a command meaning "list open files", which is used in many Unix-like systems to report a list of all open files and the processes that opened them. This open source utility was developed and supported by Vic Abell, the retired Associate Director of the Purdue University Computing Center. It works in and supports several UNIX flavors.[1]
Open files in the system include disk files, pipes, network sockets and devices opened by all processes. One use for this command is when a disk cannot be unmounted because (unspecified) files are in use. The listing of open files can be consulted (suitably filtered if necessary) to identify the process that is using the files.
# lsof /var COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME syslogd 350 root 5w VREG 222,5 0 440818 /var/adm/messages syslogd 350 root 6w VREG 222,5 339098 6248 /var/log/syslog cron 353 root cwd VDIR 222,5 512 254550 /var -- atjobs
To view the Port associated with a daemon :
# lsof -i -n -P | grep sendmail sendmail 31649 root 4u IPv4 521738 TCP *:25 (LISTEN)
From the above we can see that "sendmail" is listening on its standard port of "25".
- -i Lists IP sockets.
- -n Do not resolve hostnames (no DNS).
- -P Do not resolve port names (list port number instead of its name).
[edit] See also
- stat (Unix)
- netstat
- strace
- List of Unix programs
- Process Explorer [1] from SysInternals - the equivalent for Windows (Find menu -> Find Handle or DLL)
[edit] References
- ^ W. Richard Stevens, Bill Fenner, Andrew M. Rudoff (2003), Unix Network Programming: the Sockets networking API, Addison-Wesley Professional, ISBN 0131411551, http://books.google.com/books?vid=ISBN0131411551&id=ptSC4LpwGA0C&pg=RA1-PA897&lpg=RA1-PA897&ots=Kp7AQkfiSm&dq=Lsof&ie=ISO-8859-1&output=html&sig=bbb3jzTxdoa4IlTPpgUP17T7qVU
[edit] External links
- lsof manpage on www.netadmintools.com
- Vic Abell's homepage, author of lsof.
- Lsof FAQ [2]
- Sam Nelson's PCP script, an alternative to "lsof -i" for Solaris.
- Troubleshooting Running Systems with lsof
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