DEV Community

Janak Shrestha
Janak Shrestha

Posted on

Linux User Data Transfer

#linux

Due to an accidental data mix-up, user data was unintentionally mingled on Nautilus App Server 1 at the /home/usersdata location by the Nautilus production support team in Stratos DC. To rectify this, specific user data needs to be filtered and relocated. Here are the details:

Locate all files (excluding directories) owned by user kareem within the /home/usersdata directory on App Server 1. Copy these files while preserving the directory structure to the /ecommerce directory.

Solution

Step 1: Connect to App Server 1 (stapp01) 

ssh tony@stapp01
# Password: Ir0nM@n
Enter fullscreen mode Exit fullscreen mode

Step 2: Switch to root or use sudo 

sudo su -
# Password: Ir0nM@n
Enter fullscreen mode Exit fullscreen mode

Step 3: Create the destination directory (if it doesn't exist) 

mkdir -p /ecommerce
Enter fullscreen mode Exit fullscreen mode

Step 4: Find and copy files owned by kareem

Use the find command with -type f to locate only files (not directories) and cpio or rsync to copy while preserving directory structure:

Method 1: Using find with cpio (Recommended) 

find /home/usersdata -type f -user kareem -print0 | cpio -pdmv0 /ecommerce
Enter fullscreen mode Exit fullscreen mode

Command breakdown:

  • find /home/usersdata -type f -user kareem: Find all files owned by kareem
  • -print0: Use null character as separator (handles spaces in filenames)
  • cpio -pdmv0: Copy files in pass-through mode
    • -p: Pass-through mode (copy files)
    • -d: Create directories as needed
    • -m: Preserve modification times
    • -v: Verbose output
    • -0: Read null-terminated filenames

Method 2: Using find with tar (Alternative) 

find /home/usersdata -type f -user kareem -print0 | tar -cf - --null -T - | tar -xf - -C /ecommerce
Enter fullscreen mode Exit fullscreen mode

Method 3: Using find with rsync (if available) 

find /home/usersdata -type f -user kareem -print0 | rsync -av --files-from=- --from0 / /ecommerce/
Enter fullscreen mode Exit fullscreen mode

Step 5: Verify the copy 

# Count files copied
find /ecommerce/home/usersdata -type f -user kareem 2>/dev/null | wc -l

# List some files to verify
find /ecommerce/home/usersdata -type f -user kareem -ls 2>/dev/null | head -20

# Check directory structure preserved
ls -la /ecommerce/home/usersdata/

# Verify ownership preserved
find /ecommerce -type f -user kareem -ls 2>/dev/null
Enter fullscreen mode Exit fullscreen mode

Complete One-Line Commands

From jump host with password: 

echo 'Ir0nM@n' | ssh tony@stapp01 "sudo -S bash -c 'mkdir -p /ecommerce && find /home/usersdata -type f -user kareem -print0 | cpio -pdmv0 /ecommerce'"
Enter fullscreen mode Exit fullscreen mode

From jump host using heredoc: 

ssh tony@stapp01 << 'EOF'
echo 'Ir0nM@n' | sudo -S bash -c '
mkdir -p /ecommerce
echo "Finding and copying files owned by kareem..."
find /home/usersdata -type f -user kareem -print0 | cpio -pdmv0 /ecommerce
echo ""
echo "Verification:"
echo "Files copied:"
find /ecommerce/home/usersdata -type f -user kareem 2>/dev/null | wc -l
echo ""
echo "Sample of copied files:"
find /ecommerce/home/usersdata -type f -user kareem 2>/dev/null | head -10
'
EOF
Enter fullscreen mode Exit fullscreen mode

Step-by-Step Interactive Commands 

# Connect to stapp01
ssh tony@stapp01
# Enter password: Ir0nM@n

# Become root
sudo su -
# Enter password: Ir0nM@n

# Create destination directory
mkdir -p /ecommerce

# Find all files owned by kareem and copy preserving structure
find /home/usersdata -type f -user kareem -print0 | cpio -pdmv0 /ecommerce

# Verify the copy
echo "Number of files copied:"
find /ecommerce/home/usersdata -type f -user kareem 2>/dev/null | wc -l

echo "Directory structure preserved:"
ls -la /ecommerce/home/usersdata/

echo "Sample files copied:"
find /ecommerce/home/usersdata -type f -user kareem 2>/dev/null | head -10

# Exit back
exit
exit
Enter fullscreen mode Exit fullscreen mode

Understanding the Commands

find options explained:

  • /home/usersdata - Starting directory to search
  • -type f - Only find regular files (not directories)
  • -user kareem - Only files owned by user kareem
  • -print0 - Print with null character separator (handles spaces)

cpio options explained:

  • -p - Pass-through mode (copy files)
  • -d - Create leading directories where needed
  • -m - Preserve file modification times
  • -v - Verbose (shows what's being copied)
  • -0 - Read null-terminated filenames from stdin

Alternative Methods

Method 4: Using find with xargs and cp 

find /home/usersdata -type f -user kareem -print0 | xargs -0 -I {} cp --parents {} /ecommerce/
Enter fullscreen mode Exit fullscreen mode

Method 5: Using a simple script 

#!/bin/bash
DEST="/ecommerce"
SRC="/home/usersdata"

mkdir -p "$DEST"

find "$SRC" -type f -user kareem | while read -r file; do
    # Get relative path
    rel_path="${file#$SRC/}"
    # Create destination directory
    mkdir -p "$DEST/$(dirname "$rel_path")"
    # Copy file
    cp "$file" "$DEST/$rel_path"
    echo "Copied: $rel_path"
done
Enter fullscreen mode Exit fullscreen mode

Method 6: Using tar directly 

find /home/usersdata -type f -user kareem -exec tar -rf /tmp/kareem_files.tar {} \;
mkdir -p /ecommerce
tar -xf /tmp/kareem_files.tar -C /ecommerce
rm /tmp/kareem_files.tar
Enter fullscreen mode Exit fullscreen mode

Verification Commands

Run these to verify the operation:

# 1. Check total files copied
echo "Total files copied:"
find /ecommerce/home/usersdata -type f -user kareem 2>/dev/null | wc -l

# 2. Compare with original count
echo "Original files count:"
find /home/usersdata -type f -user kareem | wc -l

# 3. Check directory structure
echo "Directory structure:"
find /ecommerce/home/usersdata -type d 2>/dev/null

# 4. Check file ownership preserved
echo "Ownership verification:"
find /ecommerce -type f -user kareem -ls 2>/dev/null | head -5

# 5. Verify no directories were copied (only files)
echo "Checking no directories were copied:"
find /ecommerce -type d -user kareem 2>/dev/null | wc -l
# Should be 0 or minimal (only directory structure)

# 6. Check for any directories incorrectly copied as files
find /ecommerce -type f -user kareem -exec file {} \; | grep directory
# Should return no results
Enter fullscreen mode Exit fullscreen mode

Expected Output 

[root@stapp01 ~]# mkdir -p /ecommerce
[root@stapp01 ~]# find /home/usersdata -type f -user kareem -print0 | cpio -pdmv0 /ecommerce
/home/usersdata/docs/report.txt
/home/usersdata/projects/project1/config.yml
/home/usersdata/backup/data_backup.tar.gz
...
12 blocks
[root@stapp01 ~]# find /ecommerce/home/usersdata -type f -user kareem | wc -l
42
[root@stapp01 ~]# ls -la /ecommerce/home/usersdata/
total 12
drwxr-xr-x 3 root root 4096 Jul 01 10:00 .
drwxr-xr-x 3 root root 4096 Jul 01 10:00 ..
drwxr-xr-x 4 root root 4096 Jul 01 10:00 docs
drwxr-xr-x 3 root root 4096 Jul 01 10:00 projects
...
Enter fullscreen mode Exit fullscreen mode

Troubleshooting

  1. "No such file or directory": Ensure /home/usersdata exists 
   ls -la /home/usersdata
Enter fullscreen mode Exit fullscreen mode
  1. "Permission denied": Use sudo or run as root 
   sudo su -
Enter fullscreen mode Exit fullscreen mode
  1. "cpio: Not enough memory": Use tar method instead 
   find /home/usersdata -type f -user kareem -exec tar -rf /tmp/kareem_files.tar {} \;
Enter fullscreen mode Exit fullscreen mode
  1. "Invalid option": Check cpio version and options 
   cpio --version
   # If issues, use tar method
Enter fullscreen mode Exit fullscreen mode
  1. Spaces in filenames: Ensure you use -print0 and -0 options

Complete Solution Summary

The task has been completed on App Server 1 (stapp01):

  • ✅ Located all files (excluding directories) owned by user kareem in /home/usersdata
  • ✅ Copied files to /ecommerce directory
  • ✅ Preserved the directory structure
  • ✅ Verified files were copied correctly
  • ✅ Ownership maintained

The accidental data mix-up has been rectified by filtering and relocating only the files owned by user kareem to the /ecommerce directory while maintaining the original directory structure.

Top comments (0)