Monitor System I/O

• lsof

    # e.g. check pid_1, pid_2, exclude pid_3 every second (-r 1)
    # for directory ~
    lsof -p pid_1,pid_2,^pid_3 -r 1 +d ~
  
    # e.g. check localhost TCP connection to ports 80~1024 and smtp
    lsof -i tcp@0:80-1024,smtp
  
    # e.g. check dev
    lsof /dev/disk5s1
  

• fs_usage

    sudo fs_usage pid