Linux Check File Size: ls, du, stat Command Examples

Three tools. Each gives you slightly different information. Here's when to use which.

TL;DR

ls -lh file.log              # human-readable size in listing
du -sh file.log              # disk usage (may differ from file size)
stat file.log                # detailed: size, blocks, timestamps
wc -c file.log               # size in bytes only

ls -lh: Size in a File Listing

ls -lh /var/log/nginx/

-rw-r--r-- 1 www-data www-data  450M Apr 22 09:15 access.log
-rw-r--r-- 1 www-data www-data  2.3G Apr 22 08:22 error.log
-rw-r--r-- 1 www-data www-data   89K Apr 21 14:00 error.log.1

The fifth column is the file size. -h makes it human-readable (K/M/G).

# Just size and name (no other columns)
ls -lh /var/log/ | awk '{print $5, $9}'

# Sort by size
ls -lhS /var/log/          # smallest to largest
ls -lhSr /var/log/         # largest to smallest (-r reverses)

du -sh: Disk Usage

du -sh /var/log/nginx/error.log
# 2.3G    /var/log/nginx/error.log

du shows actual disk space consumed (rounded up to block size). It can differ from ls -lh for sparse files.

# Multiple files
du -sh /var/log/*

# Sort by size
du -sh /var/log/* | sort -rh | head

stat: Complete File Information

stat /var/log/nginx/error.log

  File: /var/log/nginx/error.log
  Size: 2466250752     Blocks: 4817088    IO Block: 4096   regular file
Device: 801h/2049d     Inode: 123456      Links: 1
Access: (0644/-rw-r--r--)  Uid: (33/www-data)   Gid: (33/www-data)
Access: 2026-04-22 09:15:01.234567890 +0000
Modify: 2026-04-22 09:15:42.123456789 +0000
Change: 2026-04-22 09:15:42.123456789 +0000

Key fields:

Size — file size in bytes
Blocks — 512-byte blocks allocated on disk
Access/Modify/Change — atime, mtime, ctime

Get Size in Bytes (for scripts)

# wc -c: byte count
wc -c /var/log/nginx/error.log
# 2466250752 /var/log/nginx/error.log

# stat: just the number
stat -c %s /var/log/nginx/error.log
# 2466250752

# du: in kilobytes (no -h)
du -k /var/log/nginx/error.log
# 2407552  /var/log/nginx/error.log

Real Examples

Check if a file is growing (log rotation working?)

# Size at two points in time
SIZE1=$(stat -c %s /var/log/app/app.log)
sleep 60
SIZE2=$(stat -c %s /var/log/app/app.log)
echo "Growth: $((SIZE2 - SIZE1)) bytes/minute"

Alert when a log file exceeds a threshold

#!/bin/bash
LOGFILE="/var/log/app/debug.log"
MAX_SIZE=$((500 * 1024 * 1024))  # 500MB in bytes

SIZE=$(stat -c %s "$LOGFILE" 2>/dev/null || echo 0)
if [ "$SIZE" -gt "$MAX_SIZE" ]; then
  echo "ALERT: $LOGFILE is $(du -sh $LOGFILE | cut -f1) — exceeds 500MB"
fi

Find all files over 1GB

find / -type f -size +1G -exec ls -lh {} \; 2>/dev/null

Compare apparent size vs disk usage

# Apparent size (what ls shows)
ls -lh sparsefile
# -rw-r--r-- 1 root root 10G

# Actual disk blocks used (sparse file = much less)
du -sh sparsefile
# 48K    sparsefile   ← only 48KB of actual blocks allocated

ls vs du: Why They Sometimes Differ

ls -lh shows the file's logical size (bytes of content). du -sh shows disk blocks allocated (rounded to block size, can include holes in sparse files).

For most regular files: same result. For sparse files, compressed filesystems, or files with holes: they differ. For monitoring disk usage, du is more accurate.

Common Mistakes

Mistake 1: Confusing file size with disk usage A 2GB log file uses ~2GB disk space. A 10GB sparse virtual disk image might only use 100MB of actual blocks. ls shows 10GB, du shows 100MB. Both are correct.

Mistake 2: ls -l without -h for large files

ls -l /var/log/error.log
# -rw-r--r-- 1 www 2466250752 Apr 22 error.log  ← bytes, hard to read

ls -lh /var/log/error.log
# -rw-r--r-- 1 www 2.3G Apr 22 error.log  ← human-readable

Mistake 3: Using wc -c on binary files wc -c is fine for any file — it counts bytes, not lines. But it reads the whole file, which is slow for multi-GB files. Use stat -c %s instead:

stat -c %s largefile.bin   # instant, no file read
wc -c largefile.bin        # reads entire file — slow for big files

Quick Reference

ls -lh file              # human-readable size in listing
ls -lhS dir/             # sort by size
du -sh file              # disk space used
du -sh dir/* | sort -rh  # directory sizes sorted
stat file                # full info including timestamps
stat -c %s file          # size in bytes only (for scripts)
wc -c file               # size in bytes
find / -size +1G         # find files over 1GB

Conclusion

ls -lh for quick visual check. du -sh for accurate disk usage. stat -c %s for scripting (returns bytes, no file reading needed). For finding files by size, find -size with +100M syntax is the right tool.

Related: How to Find Large Files in Linux — finding files by size across directories. Check Disk Usage in Linux: du vs df — filesystem-level vs directory-level disk usage.