Archives¶

Working with compressed files and archives: tar, gzip, zip, and more.

tar - Tape Archive¶

The standard Unix archiving tool.

Create Archives¶

# Create tar archive
tar -cvf archive.tar dir/
tar -cvf archive.tar file1 file2 dir/

# Create compressed archives
tar -czvf archive.tar.gz dir/         # gzip (most common)
tar -cjvf archive.tar.bz2 dir/        # bzip2 (better compression)
tar -cJvf archive.tar.xz dir/         # xz (best compression)

Extract Archives¶

# Extract tar
tar -xvf archive.tar
tar -xvf archive.tar -C /destination/

# Extract compressed
tar -xzvf archive.tar.gz              # gzip
tar -xjvf archive.tar.bz2             # bzip2
tar -xJvf archive.tar.xz              # xz

# Auto-detect compression
tar -xvf archive.tar.gz               # Often works without z/j/J

List Contents¶

tar -tvf archive.tar                  # List contents
tar -tzvf archive.tar.gz              # List compressed

Common Options¶

Option	Meaning
`-c`	Create archive
`-x`	Extract archive
`-t`	List contents
`-v`	Verbose
`-f`	Specify filename
`-z`	gzip compression
`-j`	bzip2 compression
`-J`	xz compression
`-C`	Change directory
`-p`	Preserve permissions
`--exclude`	Exclude pattern

Selective Operations¶

# Extract specific files
tar -xvf archive.tar path/to/file

# Extract with pattern
tar -xvf archive.tar --wildcards '*.txt'

# Exclude files
tar -czvf archive.tar.gz --exclude='*.log' --exclude='node_modules' dir/

# Exclude patterns from file
tar -czvf archive.tar.gz -X exclude.txt dir/

Practical Examples¶

# Backup with date
tar -czvf "backup-$(date +%Y%m%d).tar.gz" /data/

# Archive preserving permissions
tar -cpzvf archive.tar.gz dir/

# Extract without top directory
tar -xzvf archive.tar.gz --strip-components=1

# Create from list of files
tar -czvf archive.tar.gz -T files.txt

# View without extracting
tar -tzvf archive.tar.gz | grep "pattern"

# Add to existing archive (uncompressed only)
tar -rvf archive.tar newfile

gzip / gunzip¶

Compress single files:

gzip file.txt                         # Creates file.txt.gz
gzip -k file.txt                      # Keep original
gzip -d file.txt.gz                   # Decompress
gunzip file.txt.gz                    # Same as gzip -d
gzip -l file.txt.gz                   # Show compression stats

Options¶

gzip -1 file.txt                      # Fastest compression
gzip -9 file.txt                      # Best compression
gzip -c file.txt > file.txt.gz        # Output to stdout
gzip -r dir/                          # Recursive

zcat / zless / zgrep¶

Work with gzipped files without extracting:

zcat file.txt.gz                      # View contents
zless file.txt.gz                     # Page through
zgrep "pattern" file.txt.gz           # Search in compressed

bzip2 / bunzip2¶

Better compression than gzip:

bzip2 file.txt                        # Creates file.txt.bz2
bzip2 -k file.txt                     # Keep original
bzip2 -d file.txt.bz2                 # Decompress
bunzip2 file.txt.bz2                  # Same as bzip2 -d

Related tools: bzcat, bzless, bzgrep

xz / unxz¶

Best compression ratio:

xz file.txt                           # Creates file.txt.xz
xz -k file.txt                        # Keep original
xz -d file.txt.xz                     # Decompress
unxz file.txt.xz                      # Same as xz -d
xz -l file.txt.xz                     # Show info

Options:

xz -0 file.txt                        # Fastest
xz -9 file.txt                        # Best compression (slow)
xz -T 4 file.txt                      # Use 4 threads

Related tools: xzcat, xzless, xzgrep

zip / unzip¶

Cross-platform archive format:

Creating Archives¶

zip archive.zip file1 file2           # Add files
zip -r archive.zip dir/               # Recursive (directory)
zip -j archive.zip dir/*              # No directory structure
zip -e archive.zip file               # Encrypted (prompts for password)
zip -9 archive.zip file               # Best compression

Extracting¶

unzip archive.zip                     # Extract all
unzip archive.zip -d /destination/    # Extract to directory
unzip archive.zip file.txt            # Extract specific file
unzip -l archive.zip                  # List contents
unzip -t archive.zip                  # Test integrity
unzip -o archive.zip                  # Overwrite without prompting

Managing Archives¶

zip -u archive.zip newfile            # Update/add file
zip -d archive.zip file               # Delete from archive
zip -sf archive.zip                   # Show files (like -l)

7z (p7zip)¶

High compression, many formats:

Installation¶

# macOS
brew install p7zip

# Debian/Ubuntu
apt install p7zip-full

Usage¶

7z a archive.7z dir/                  # Create archive
7z x archive.7z                       # Extract
7z l archive.7z                       # List contents
7z t archive.7z                       # Test integrity
7z e archive.7z                       # Extract (flat)

Options¶

7z a -p archive.7z dir/               # Password protected
7z a -mx=9 archive.7z dir/            # Maximum compression
7z a -v100m archive.7z dir/           # Split into 100MB volumes

Compression Comparison¶

Format	Extension	Compression	Speed	Compatibility
gzip	.gz	Good	Fast	Universal
bzip2	.bz2	Better	Slower	Common
xz	.xz	Best	Slowest	Modern systems
zip	.zip	Good	Fast	Universal (Windows)
7z	.7z	Best	Slow	Needs 7zip

When to Use What¶

tar.gz: Default choice for Unix backups and transfers
tar.xz: When size matters more than time
zip: Sharing with Windows users
7z: Maximum compression needed

Practical Patterns¶

Backup Script¶

#!/usr/bin/env bash
backup_dir="/backup"
source_dir="/data"
date_stamp=$(date +%Y%m%d_%H%M%S)
archive="${backup_dir}/backup_${date_stamp}.tar.gz"

tar -czvf "$archive" \
    --exclude='*.log' \
    --exclude='tmp/*' \
    "$source_dir"

echo "Backup created: $archive"

Extract Based on Extension¶

extract() {
    local file="$1"
    if [[ ! -f "$file" ]]; then
        echo "Error: '$file' not found"
        return 1
    fi

    case "$file" in
        *.tar.bz2)  tar -xjvf "$file" ;;
        *.tar.gz)   tar -xzvf "$file" ;;
        *.tar.xz)   tar -xJvf "$file" ;;
        *.tar)      tar -xvf "$file" ;;
        *.bz2)      bunzip2 "$file" ;;
        *.gz)       gunzip "$file" ;;
        *.xz)       unxz "$file" ;;
        *.zip)      unzip "$file" ;;
        *.7z)       7z x "$file" ;;
        *.rar)      unrar x "$file" ;;
        *)          echo "Unknown format: $file" && return 1 ;;
    esac
}

Compress with Progress¶

# Using pv for progress
tar -cf - dir/ | pv -s $(du -sb dir/ | awk '{print $1}') | gzip > archive.tar.gz

Split Large Archives¶

# Create split archive
tar -czvf - largedir/ | split -b 100M - archive.tar.gz.

# Rejoin and extract
cat archive.tar.gz.* | tar -xzvf -

Transfer with Compression¶

# Compress and transfer
tar -czvf - dir/ | ssh user@host 'cat > /path/archive.tar.gz'

# Transfer and extract
tar -czvf - dir/ | ssh user@host 'tar -xzvf - -C /destination/'

# Using rsync with compression
rsync -avz dir/ user@host:/path/

Compare Archive Contents¶

# List files in both
diff <(tar -tzf archive1.tar.gz | sort) <(tar -tzf archive2.tar.gz | sort)

Try It¶

Create tar.gz:

mkdir -p /tmp/test_archive
echo "test" > /tmp/test_archive/file.txt
tar -czvf /tmp/test.tar.gz /tmp/test_archive
tar -tzvf /tmp/test.tar.gz
rm -rf /tmp/test_archive /tmp/test.tar.gz

Compress single file:

echo "test content" > /tmp/test.txt
gzip -k /tmp/test.txt
ls -la /tmp/test.txt*
zcat /tmp/test.txt.gz
rm /tmp/test.txt*

Create zip:

echo "test" > /tmp/test.txt
zip /tmp/test.zip /tmp/test.txt
unzip -l /tmp/test.zip
rm /tmp/test.txt /tmp/test.zip

Summary¶

Task	Command
Create tar.gz	`tar -czvf archive.tar.gz dir/`
Extract tar.gz	`tar -xzvf archive.tar.gz`
List tar contents	`tar -tzvf archive.tar.gz`
Create zip	`zip -r archive.zip dir/`
Extract zip	`unzip archive.zip`
Compress file	`gzip file`
Decompress file	`gunzip file.gz`
View compressed	`zcat file.gz`

Compression flags for tar:

Flag	Format	Extension
`-z`	gzip	.tar.gz, .tgz
`-j`	bzip2	.tar.bz2
`-J`	xz	.tar.xz