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Wildcard and Linux Notation Support

This document describes the wildcard and Linux notation support added to the PureSimulator virtual terminal.

Supported Wildcards

Asterisk (*) - Multiple Character Wildcard

The asterisk matches zero or more characters in filenames and paths.

Examples:

  • ls *.ppkg - Lists all files ending with .ppkg
  • ls file* - Lists all files starting with "file"
  • ls /dev/sd* - Lists all devices starting with "sd" (e.g., sda1, sdb1)
  • ls *test*.txt - Lists all .txt files containing "test"

Question Mark (?) - Single Character Wildcard

The question mark matches exactly one character in filenames and paths.

Examples:

  • ls file?.txt - Matches file1.txt, fileA.txt, but not file10.txt
  • ls test?.log - Matches test1.log, testa.log, etc.
  • ls /dev/sd?1 - Matches sda1, sdb1, sdc1, etc.

Linux Path Notation

Current Directory (.)

Represents the current working directory.

Examples:

  • ls . - Lists files in the current directory
  • cp /mnt/file.txt . - Copies file.txt to the current directory

Parent Directory (..)

Represents the parent directory of the current working directory.

Examples:

  • cd .. - Changes to the parent directory
  • ls .. - Lists files in the parent directory
  • cp ../file.txt . - Copies a file from the parent directory to current

Implementation Details

The wildcard support has been implemented in the following components:

1. VirtualDirectory.cs

  • Added GetMatchingFiles(string pattern) method for pattern matching
  • Added WildcardMatch(string text, string pattern) for * and ? support

2. ChassisCommandsExtension.cs

  • Enhanced MatchesWildcard() to support both * and ?
  • Updated FindAndListFiles() to handle wildcard patterns in file paths
  • Added support for wildcards in /dev/ directory listings

3. VirtualFileSystem.cs

  • Updated FindFilesRecursive() to use wildcard matching
  • Added WildcardMatch() method for file searching
  • Path normalization already supports . and .. through NormalizePath()

4. VirtualFileSystemHandler.cs

  • Added HandleWildcardLs() for ls command with wildcards
  • Added WildcardMatchPublic() helper method
  • Enhanced HandleLsCommand() to detect and process wildcards

Usage in Commands

ls command

ls *.ppkg                    # List all .ppkg files
ls /dev/sd*                  # List all sd devices
ls file?.txt                 # List files matching pattern
ls /mnt/*                    # List all files in /mnt

cp command

cp /mnt/*.ppkg .             # Copy all .ppkg files from /mnt to current dir
cp ../file.txt .             # Copy from parent directory

Tab Completion

Double-tap Tab to autocomplete filenames (existing functionality). The autocomplete works with partial filenames and paths.

Wildcard Matching Algorithm

The wildcard matching uses a backtracking algorithm that:

  1. Matches ? to exactly one character
  2. Matches * to zero or more characters
  3. Handles multiple wildcards in the same pattern
  4. Is case-sensitive (matching Linux behavior)
  5. Supports complex patterns like purity-?.*.*.ppkg

Edge Cases and Limitations

Supported:

  • ✓ Multiple wildcards in one pattern: *test*.log
  • ✓ Mixed wildcards: file?.tx*
  • ✓ Wildcards at any position: *, test*, *test, *test*
  • ✓ Empty matches with *: * matches everything including empty
  • ✓ Directory navigation with . and ..
  • ✓ Relative and absolute paths

Notes:

  • Wildcard matching is case-sensitive (Linux standard behavior)
  • The ? wildcard requires exactly one character (won't match zero characters)
  • Pattern *.ppkg matches file.ppkg and .ppkg (including hidden files starting with .)
  • Patterns are matched against filenames only, not full paths (except in specific commands)

Examples of Edge Cases:

# Pattern: file?.txt
file1.txt    → matches (? = 1)
fileA.txt    → matches (? = A)
file.txt     → no match (? requires exactly 1 character)
file10.txt   → no match (? matches only 1 character, not 10)

# Pattern: *.ppkg
test.ppkg    → matches
.ppkg        → matches (. at start is a character)
ppkg         → no match (no . before ppkg)

# Pattern: *
everything   → matches (including empty if listing directories)

Testing Examples

To test the wildcard support in the PureSimulator terminal:

1. List devices with wildcards:

ls /dev/sd*          # Lists sda1, sdb1, etc.
ls /dev/sd?1         # Lists sda1, sdb1, sdc1 (but not sdab1)
ls /dev/s*           # Lists all devices starting with 's'

2. List files with patterns:

ls *.ppkg                # Lists all .ppkg files
ls purity-?.*.*.ppkg     # Lists purity-1.2.3.ppkg, purity-6.5.4.ppkg, etc.
ls file?.txt             # Lists file1.txt, fileA.txt (but not file10.txt)
ls *test*                # Lists all files containing 'test'

3. Use current and parent directory notation:

cd /home/pureeng
ls .                     # Lists current directory
ls ..                    # Lists parent directory (/home)
cd ..                    # Changes to parent directory
cp ../file.txt .         # Copies file from parent to current

4. Copy files with wildcards:

mount /dev/sdb1 /mnt
cp /mnt/*.ppkg .         # Copies all .ppkg files from /mnt to current directory
cp /mnt/purity-6.*.ppkg .   # Copies specific version patterns
cp /mnt/file?.txt .      # Copies files matching single-char pattern

5. Complex wildcard patterns:

ls purity-[0-9].*.*.ppkg    # Using wildcards for version matching
ls *config*.xml             # Files containing 'config' with .xml extension
cp /mnt/*backup* .          # Copy all files with 'backup' in the name

6. Tab completion:

# Type partial filename and double-tap Tab to autocomplete
ls puri<Tab><Tab>        # Autocompletes to purity-*.ppkg files
cp /mnt/fil<Tab><Tab>    # Autocompletes to file names starting with 'fil'

7. Navigating with . and .. :

cd /opt/Purity/bin
cd ../../etc            # Go up two levels, then into etc
ls ../../../home        # List files three levels up, then in home
pwd                     # Shows current directory after navigation

Real-World Usage Scenarios

Scenario 1: Installing Purity from USB

# Mount the USB drive
mount /dev/sdb1 /mnt

# List available Purity versions
ls /mnt/purity-*.ppkg

# Install a specific version pattern
pureinstall /mnt/purity-6.5.*.ppkg

# Copy all installation packages for backup
cp /mnt/*.ppkg .

Scenario 2: Managing Log Files

# View all log files
ls /var/log/*.log

# View logs from current day
ls /var/log/*$(date +%Y%m%d)*.log

# Clean up old logs
rm /var/log/old_*.log

Scenario 3: Working with Configuration Files

# List all config files
ls /etc/*.conf

# Backup configuration files
cp /etc/*.conf /root/backup/

# Find specific config file
ls /etc/*network*.conf

Scenario 4: Troubleshooting with Wildcards

# Check all drive statuses
ls /dev/sd*

# View device information
cat /dev/sd?1

# List all mounted filesystems
df | grep /dev/sd*