stat Command Linux: Complete Guide to Display File and Filesystem Status Information

The stat command is a powerful Linux utility that displays detailed information about files and filesystems. Unlike basic commands like ls, stat provides comprehensive metadata including file permissions, ownership, timestamps, size, and filesystem details. This command is essential for system administrators, developers, and anyone who needs in-depth file analysis.

Understanding the stat Command

The stat command reads the inode information of a file or filesystem and displays it in a human-readable format. It accesses the same information that other commands use but presents it comprehensively in one place.

Basic Syntax

stat [OPTION]... FILE...

The simplest usage involves specifying a filename:

stat filename.txt

Default stat Output Explanation

When you run stat on a file, it displays several pieces of information. Let’s examine each component:

$ stat example.txt
  File: example.txt
  Size: 1024        Blocks: 8          IO Block: 4096   regular file
Device: 802h/2050d  Inode: 1234567     Links: 1
Access: (0644/-rw-r--r--)  Uid: (1000/username)   Gid: (1000/username)
Access: 2025-08-25 08:00:15.123456789 +0530
Modify: 2025-08-25 07:55:30.987654321 +0530
Change: 2025-08-25 07:55:30.987654321 +0530
 Birth: 2025-08-25 07:55:30.987654321 +0530

Output Fields Breakdown

• File: The filename or path
• Size: File size in bytes
• Blocks: Number of filesystem blocks allocated
• IO Block: Optimal I/O block size
• Device: Device ID in hexadecimal and decimal
• Inode: Inode number
• Links: Number of hard links
• Access: File permissions and ownership
• Access time: Last access timestamp
• Modify time: Last modification timestamp
• Change time: Last status change timestamp
• Birth: File creation time (if supported)

Essential stat Command Options

Format Output (-c, –format)

The -c option allows custom formatting using format sequences:

$ stat -c "%n %s %U %G" example.txt
example.txt 1024 username username

Common format sequences:

• %n – File name
• %s – Total size in bytes
• %U – User name of owner
• %G – Group name of owner
• %a – Access rights in octal
• %A – Access rights in human readable form
• %x – Time of last access
• %y – Time of last modification
• %z – Time of last change

Filesystem Information (-f, –file-system)

Display filesystem information instead of file information:

$ stat -f /home
  File: "/home"
    ID: 1234567890abcdef Namelen: 255     Type: ext4
Block size: 4096       Fundamental block size: 4096
Blocks: Total: 10485760   Free: 5242880    Available: 4718592
Inodes: Total: 2621440    Free: 2097152

Terse Output (-t, –terse)

Generate machine-readable output:

$ stat -t example.txt
example.txt 1024 8 81a4 1000 1000 802 1234567 1 0 0 1724555415 1724555130 1724555130 1724555130 4096

Practical Examples and Use Cases

Checking File Permissions

Display only permissions in octal format:

$ stat -c "%a %n" /etc/passwd
644 /etc/passwd

Show detailed permission information:

$ stat -c "%A %n" /usr/bin/sudo
-rwsr-xr-x /usr/bin/sudo

Monitoring File Changes

Compare modification times of multiple files:

$ stat -c "%y %n" file1.txt file2.txt file3.txt
2025-08-25 08:00:15.123456789 +0530 file1.txt
2025-08-25 07:30:22.987654321 +0530 file2.txt
2025-08-25 08:15:45.456789123 +0530 file3.txt

Finding File Size Information

Display file sizes in a readable format:

$ stat -c "%s bytes - %n" *.log
2048 bytes - access.log
4096 bytes - error.log
1024 bytes - debug.log

Identifying File Types

Determine file types using stat:

$ stat -c "%F %n" /dev/sda1 /tmp /etc/passwd
block special file /dev/sda1
directory /tmp
regular file /etc/passwd

Advanced stat Usage

Scripting with stat

Create a script to monitor file changes:

#!/bin/bash
# File monitoring script

file="$1"
if [[ -f "$file" ]]; then
    echo "File: $(stat -c "%n" "$file")"
    echo "Size: $(stat -c "%s" "$file") bytes"
    echo "Modified: $(stat -c "%y" "$file")"
    echo "Permissions: $(stat -c "%a" "$file")"
else
    echo "File not found: $file"
fi

Comparing Files

Compare two files’ metadata:

$ stat -c "%n: Size=%s, Inode=%i, Links=%h" file1.txt file2.txt
file1.txt: Size=1024, Inode=1234567, Links=1
file2.txt: Size=2048, Inode=1234568, Links=1

Filesystem Analysis

Analyze filesystem usage and capacity:

$ stat -f -c "Filesystem: %n | Type: %T | Block size: %s | Total blocks: %b | Free blocks: %f" /
Filesystem: / | Type: ext4 | Block size: 4096 | Total blocks: 10485760 | Free blocks: 5242880

Understanding Timestamps

The Three Timestamps

Linux tracks three different timestamps for each file:

• Access time (atime): Last time file was read
• Modify time (mtime): Last time file content was modified
• Change time (ctime): Last time file metadata was changed

Timestamp Examples

$ stat -c "Access: %x | Modify: %y | Change: %z" document.pdf
Access: 2025-08-25 08:00:15.123456789 +0530 | Modify: 2025-08-24 15:30:22.987654321 +0530 | Change: 2025-08-24 15:30:22.987654321 +0530

Common stat Command Combinations

Finding Recently Modified Files

Combine with find to locate recently changed files:

$ find /home/user -type f -exec stat -c "%y %n" {} \; | sort -r | head -10

Backup Verification

Verify file integrity after backup:

$ stat -c "%n %s %Y" original.txt backup.txt
original.txt 1024 1724555130
backup.txt 1024 1724555130

stat vs Other Commands

stat vs ls

Troubleshooting Common Issues

Permission Denied

When stat fails with permission errors:

$ stat /root/private.txt
stat: cannot stat '/root/private.txt': Permission denied

Solution: Use sudo or check file permissions:

$ sudo stat /root/private.txt

File Not Found

For non-existent files:

$ stat nonexistent.txt
stat: cannot stat 'nonexistent.txt': No such file or directory

Symbolic Links

By default, stat follows symbolic links. To examine the link itself:

$ stat -L symlink.txt    # Follow the link
$ stat symlink.txt       # Examine the link itself

Performance Considerations

The stat command is generally fast as it reads inode information directly. However, when processing many files, consider:

• Use terse format (-t) for machine processing
• Specify only needed format sequences with -c
• Avoid unnecessary filesystem access for large directory trees

Best Practices

Security Analysis

Use stat for security auditing:

$ stat -c "%a %U:%G %n" /etc/shadow
640 root:shadow /etc/shadow

System Monitoring

Monitor critical system files:

$ stat -c "%z %n" /etc/passwd /etc/shadow /etc/group
2025-08-24 10:30:15.123456789 +0530 /etc/passwd
2025-08-24 10:30:15.234567890 +0530 /etc/shadow
2025-08-24 10:30:15.345678901 +0530 /etc/group

Backup Scripts

Include metadata verification in backup scripts:

#!/bin/bash
# Backup verification script
original="$1"
backup="$2"

orig_size=$(stat -c "%s" "$original")
back_size=$(stat -c "%s" "$backup")

if [[ "$orig_size" == "$back_size" ]]; then
    echo "Backup verified: sizes match"
else
    echo "Backup failed: size mismatch"
fi

Conclusion

The stat command is an indispensable tool for Linux system administration and file management. Its ability to provide comprehensive file and filesystem information makes it valuable for troubleshooting, monitoring, and automation tasks. Whether you’re checking permissions, analyzing timestamps, or writing system scripts, mastering stat will enhance your Linux command-line proficiency.

Practice using different options and format strings to become proficient with this powerful utility. The detailed information provided by stat often reveals insights that other commands cannot provide, making it an essential addition to any Linux user’s toolkit.