How to execute an equivalent function of Xcode's Instruments > "File Activity" in shell?
Have you tried fs_usage with -f filesys or diskio options?


  The fs_usage utility presents an ongoing display of system call usage information pertaining to filesystem activity.  It requires root privileges due to the kernel tracing facility it uses to operate.  By default, the activity monitored includes all system processes except the running fs_usage process, Terminal, telnetd, telnet, sshd, rlogind, tcsh, csh, sh, and zsh.  These defaults can be overridden such that output is limited to include or exclude a list of processes specified by the user.