fsnotifywatch - Linux

Overview

fsnotifywatch is a Linux command-line tool for monitoring changes to files and directories. It leverages the inotify kernel interface to generate events when file system events occur, providing real-time notifications of file system changes.

Syntax

fsnotifywatch [-options] <directory> <command>

Options/Flags

  • -m, –modify: Monitor file modifications.
  • -d, –delete: Monitor file deletions.
  • -c, –create: Monitor file creations.
  • -a, –all: Monitor all events (modification, deletion, creation).
  • -r, –recursive: Monitor subdirectories and files recursively.
  • -e, –event=<event_mask>: Specify custom event mask. See man inotify for available masks.
  • -t, –timeout=: Set timeout for event monitoring (default: 10 minutes).
  • -l, –logging: Enable logging to syslog (default: off).

Examples

Example 1: Monitor a single file for changes

fsnotifywatch -m /tmp/my_file echo "File changed"

Example 2: Recursively monitor a directory

fsnotifywatch -r -a /tmp/my_dir echo "Event occurred in /tmp/my_dir"

Example 3: Monitor custom events and set timeout

fsnotifywatch -e IN_ACCESS,IN_CREATE -t 300 /tmp/my_dir echo "Event occurred: IN_ACCESS or IN_CREATE"

Common Issues

Issue: No events are triggered.

Solution: Ensure that the directory you are monitoring exists and has proper permissions. Also, check the event mask to ensure it matches the desired events.

Issue: Events are missed or delayed.

Solution: Increase the timeout value to provide more time for events to be processed. The default timeout may not be sufficient for large file systems or heavy workload.

Integration

fsnotifywatch can be integrated with other tools for advanced tasks:

  • inotify-tools: Use the inotifywait command from inotify-tools to watch for specific events and perform custom actions.
  • shell scripts: Monitor file system changes and execute arbitrary shell commands in response to events.
  • daemon processes: Create long-running processes that watch for file system changes and provide notifications or perform actions accordingly.

Related Commands

  • lsof: Lists open files and processes accessing them.
  • inotifywait: Monitors file system events with a user-defined event mask.
  • strace: Traces system calls made by a process, including file system operations.