Lsof

lsof list open files and network connections.

Basic commands

• lsof -t /path/to/file
• lsof /path/to/file

List all open files by a specific process:

• lsof -p PID

• lsof -u USERNAME

Network related

• lsof -i

Open TCP ports:

• lsof -iTCP -sTCP:LISTEN -P -n

Open UDP ports:

• lsof -iUDP -P -n

Related commands:

• netstat, ss and netstat
• proc

Activities

1. Read lsof questions on StackExchange: https://unix.stackexchange.com/questions/tagged/lsof?tab=Votes
2. Review further examples in https://www.thegeekstuff.com/2012/08/lsof-command-examples/

See also

• lsof,strace, auditctl, fuser
• kill
• ip [link, route], ifconfig netstat ss lsof ping ethtool mii-tool arping nmcli(RHEL) route networkctl, netplan, tc, networkd-dispatcher
• file, File system, directory, touch, mkdir, ls, ln truncate, fallocate, split, stat, inode, File descriptor, superblock, block size (blockdev), fuser, lsof, scrub, chattr, ulimit (nofiles), cp, mv, file (command), mkfifo, chmod

http://man7.org/linux/man-pages/man8/lsof.8.html

https://www.thegeekstuff.com/2012/08/lsof-command-examples/