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In Linux systems, particularly RHEL, you can check the last modifying user through several methods. The most straightforward approach is using the stat command combined with file ownership information.

# Basic file status information
stat filename.txt

# Output will show modification time but not user
  File: filename.txt
  Size: 4096       Blocks: 8          IO Block: 4096   regular file
  Device: fd00h/64768d    Inode: 1835011     Links: 1
  Access: 2023-05-15 14:30:22.000000000 -0400
  Modify: 2023-05-15 14:30:22.000000000 -0400
  Change: 2023-05-15 14:30:22.000000000 -0400

For comprehensive user tracking, enable the auditd service:

# Install auditd if not present
sudo yum install audit

# Start and enable the service
sudo systemctl start auditd
sudo systemctl enable auditd

# Add a watch rule for specific files
sudo auditctl -w /path/to/file -p wa -k file-modifications

# Check audit logs
sudo ausearch -k file-modifications | tail -20

When auditd isn't available, check ownership changes which often coincide with modifications:

# Find files modified in last 24 hours with owner info
find /path/to/dir -type f -mtime -1 -exec ls -l {} \;

# Sample output showing owner (user1) and modification time
-rw-r--r-- 1 user1 group1 1024 May 15 14:30 /path/to/file

For critical files, consider implementing inotifywait monitoring:

# Install inotify-tools
sudo yum install inotify-tools

# Monitor a directory for changes
inotifywait -m /path/to/watch -e modify -e attrib -e move -e create -e delete --format '%T %e %f %u' --timefmt '%F %T' | while read line
do
    echo "$(date '+%F %T') - $line" >> /var/log/file_changes.log
done

Remember these key points:

• Standard Linux file systems don't natively track modification users
• Auditd adds overhead but provides comprehensive logging
• Ownership changes don't always mean content modification
• For compliance requirements, implement proper auditing early

In Linux systems, particularly RHEL (Red Hat Enterprise Linux), you can determine the last user who modified a file using several methods. The most straightforward approach is to examine the file's metadata and system logs.

The stat command displays detailed file information, including timestamps:

stat filename

Example output:


File: filename
Size: 4096 Blocks: 8 IO Block: 4096 regular file
Device: fd00h/64768d Inode: 262145 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 1000/ username) Gid: ( 1000/ username)
Access: 2023-05-15 14:30:22.123456789 +0000
Modify: 2023-05-15 14:35:18.987654321 +0000
Change: 2023-05-15 14:35:18.987654321 +0000


For more comprehensive tracking, you can use the Linux audit daemon (auditd):


# Install auditd if not present
sudo yum install audit

# Search the audit logs
sudo ausearch -k file_modifications | tail -20


System logs might contain information about file modifications:


grep filename /var/log/messages
grep filename /var/log/secure


For real-time monitoring, consider inotify tools:


# Install inotify-tools
sudo yum install inotify-tools

# Monitor a file for changes
inotifywait -m -e modify /path/to/file


Here's a simple bash script to track file modifications:


#!/bin/bash
FILE="/path/to/file"
LAST_MOD=$(stat -c %y "$FILE")
LAST_USER=$(ls -l "$FILE" | awk '{print $3}')
echo "File $FILE was last modified at $LAST_MOD by user $LAST_USER"


For enterprise environments, consider:

• SELinux context tracking
• Commercial solutions like Splunk or ELK stack
• Version control systems (Git, SVN) for critical files