file-operations

# File and Directory Operations ## Overview Linux file system operation skills, including file search, batch operations, permission management, etc. ## File Search ### find Command ```bash # Search by name find /path -name "*.log" find /path -iname "*.LOG" # Case insensitive # Search by type find /path -type f # Files find /path -type d # Directories find /path -type l # Symbolic links # Search by time find /path -mtime -7 # Modified within 7 days find /path -mtime +30 # Modified more than 30 days ago find /path -mmin -60 # Modified within 60 minutes # Search by size find /path -size +100M # Larger than 100MB find /path -size -1k # Smaller than 1KB # Combined conditions find /path -name "*.log" -mtime +7 -size +10M ``` ### locate Command ```bash # Quick search (requires database update) locate filename updatedb # Update database # Case insensitive locate -i filename ``` ## File Operations ### Basic Operations ```bash # Copy cp file1 file2 cp -r dir1 dir2 # Recursive copy directory cp -p file1 file2 # Preserve attributes # Move/Rename mv file1 file2 mv file1 /path/to/dest/ # Delete rm file rm -rf dir # Recursive force delete rm -i file # Interactive confirmation # Create touch file # Create empty file mkdir -p dir1/dir2/dir3 # Recursive create directories ``` ### Batch Operations ```bash # Batch rename rename 's/old/new/' *.txt for f in *.txt; do mv "$f" "${f%.txt}.md"; done # Batch delete find /path -name "*.tmp" -delete find /path -name "*.log" -mtime +30 -exec rm {} \; # Batch copy find /src -name "*.conf" -exec cp {} /dest/ \; ``` ## File Content ### View Files ```bash cat file # Full content head -n 20 file # First 20 lines tail -n 20 file # Last 20 lines tail -f file # Real-time follow less file # Paginated view # Statistics wc -l file # Line count wc -w file # Word count wc -c file # Byte count ``` ### File Comparison ```bash diff file1 file2 diff -u file1 file2 # Unified format diff -r dir1 dir2 # Compare directories # Side-by-side comparison sdiff file1 file2 vimdiff file1 file2 ``` ## Permission Management ### View Permissions ```bash ls -la stat file ``` ### Modify Permissions ```bash # Numeric mode chmod 755 file # rwxr-xr-x chmod 644 file # rw-r--r-- # Symbolic mode chmod u+x file # Add execute for user chmod g-w file # Remove write for group chmod o=r file # Set read-only for others chmod a+r file # Add read for all # Recursive modify chmod -R 755 dir ``` ### Modify Owner ```bash chown user file chown user:group file chown -R user:group dir # Recursive modify ``` ## Common Scenarios ### Scenario 1: Clean Up Large Files ```bash # Find files larger than 100MB find / -type f -size +100M -exec ls -lh {} \; 2>/dev/null # Find and sort by size du -ah /path | sort -rh | head -20 ``` ### Scenario 2: Find Recently Modified Files ```bash # Files modified within 24 hours find /path -type f -mtime -1 # Sort by modification time ls -lt /path | head -20 ``` ### Scenario 3: Batch Replace File Content ```bash # Single file replacement sed -i 's/old/new/g' file # Batch replacement find /path -name "*.conf" -exec sed -i 's/old/new/g' {} \; ``` ## Troubleshooting | Problem | Solution | |---------|----------| | Permission denied | Use `sudo` or check file permissions | | Disk space full | `df -h`, `du -sh *` to find large files | | Special characters in filename | Use quotes or escape `rm "file name"` | | Slow deletion of many files | Use `rsync --delete` or `find -delete` |