How to Use Tar and Cpio for Archiving on Linux

When managing a Linux system, creating archives is an essential skill for backup operations, file distribution, and system administration. Two powerful Linux archiving tools stand out: tar and cpio. While both can create archives, they serve different purposes and excel in specific scenarios.

Understanding Tar: The Tape Archive

The tar command is probably the most common archiving tool you'll encounter on Linux systems. Originally designed for tape drives (hence "Tape ARchive"), tar creates a single file from multiple files and directories while preserving file permissions, ownership, and directory structure.

Basic Tar Operations

Here are the essential tar operations every Linux administrator should know:

# Create an archive
tar -cvf backup.tar /home/user/documents

# Extract an archive
tar -xvf backup.tar

# List contents without extracting
tar -tvf backup.tar

# Create compressed archive with gzip
tar -czf backup.tar.gz /home/user/documents

# Extract compressed archive
tar -xzf backup.tar.gz

The common options break down as follows:

• -c: Create archive
• -x: Extract archive
• -v: Verbose output
• -f: Specify filename
• -z: Compress with gzip
• -t: List contents

When to Use Tar

Tar excels when you need to:

• Archive entire directory structures
• Preserve file permissions and ownership
• Create compressed backups
• Distribute software packages

Understanding Cpio: Copy In, Copy Out

The cpio command operates differently from tar. Instead of specifying files on the command line, cpio reads filenames from standard input, making it incredibly flexible for complex file selection scenarios.

Basic Cpio Operations

Cpio has three modes of operation:

# Copy-out mode (create archive)
find /home/user -name "*.txt" | cpio -ov > textfiles.cpio

# Copy-in mode (extract archive)
cpio -iv < textfiles.cpio

# Copy-pass mode (copy files to another location)
find /source -name "*.log" | cpio -pdv /destination

Key cpio options include:

• -o: Copy-out (create)
• -i: Copy-in (extract)
• -p: Copy-pass (copy files)
• -v: Verbose output
• -d: Create directories as needed

When to Use Cpio

Cpio shines when you need to:

• Archive files based on complex criteria using find
• Create archives from file lists
• Handle special file types (device files, pipes)
• Work with backup systems that require specific formats

Practical Scenarios

Scenario 1: Daily Home Directory Backup

# Using tar for complete directory backup
tar -czf /backup/home_$(date +%Y%m%d).tar.gz /home/user

Scenario 2: Archiving Only Modified Files

# Using cpio with find to archive files modified in last 7 days
find /var/log -mtime -7 -type f | cpio -ov > recent_logs.cpio

Scenario 3: System Configuration Backup

# Using tar to backup system configuration
tar -czf /backup/etc_backup.tar.gz /etc

Choosing Between Tar and Cpio

Use tar when you want simplicity and are archiving complete directories or well-defined file sets. It's more intuitive and widely supported.

Choose cpio when you need fine-grained control over which files to archive, especially when combining with find commands for complex file selection criteria.

What's Next

Now that you understand the basics of tar and cpio for archiving, the next step is learning about automated backup strategies using cron jobs and backup scripts. We'll also explore how to implement incremental backups and restoration procedures for complete system recovery scenarios.

Tools and resources for this topic

• CompTIA Linux+ Study Guide — Comprehensive Linux+ exam preparation covering system administration, security, and scripting.